feat(dashboard): editable task documents & project files in Artifacts view; fix Add-comment CSS-order regression

- Task Documents right pane gains in-place editing with the shared CodeMirror
  FileEditor (Save via PUT /tasks/:id/documents/:key); task documents now
  render markdown by default.
- Project Files pane is editable the same way via the project workspace file
  API, replacing the Read-only badge contract.
- Fix "Add comment" doing nothing again: `.selection-comment-trigger:active`
  tied the global `.btn:active` at (0,2,0) and lost to a bundle-order flip,
  teleporting the trigger mid-press so click never fired. `:active` rules now
  use `.btn.selection-comment-trigger` (0,3,0); regression test asserts the
  prefix so a plain-selector revert fails.
- Align the task-document header: path box and Plain/Edit (Cancel/Save)
  actions share one row, meta line sits below.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.changeset/artifacts-doc-editing-and-comment-fix.md

@@ -0,0 +1,7 @@
+---
+"@runfusion/fusion": minor
+---
+
+summary: Task documents and project files are now editable in the Artifacts view, task documents render markdown by default, and the select-to-comment "Add comment" button works again.
+category: feature
+dev: DocumentsView embeds the shared CodeMirror FileEditor for task-document (PUT /tasks/:id/documents/:key) and project-file (project workspace file API) edits. The Add comment no-op was a CSS bundle-order regression — `.btn:active` out-ordered the equal-specificity trigger rule; the `:active` rules now use `.btn.selection-comment-trigger` (0,3,0) with a test asserting the prefix.

packages/dashboard/app/components/DocumentsView.css

@@ -305,6 +305,29 @@ Artifacts controls are the first page content below the shared header, so add a
   gap: var(--space-sm);
 }
 
+/*
+FNXC:DocumentsView 2026-07-11-13:40:
+Task-document header actions group the Markdown/Plain toggle with the new Edit (and Cancel/Save while editing) buttons so the in-place CodeMirror editing controls stay in the header instead of a second toolbar. The editor container mirrors .artifacts-gallery-viewer-editor sizing so the embedded FileEditor gets real height inside the right pane.
+*/
+.documents-task-document-actions {
+  display: flex;
+  align-items: center;
+  gap: var(--space-sm);
+  flex-shrink: 0;
+}
+
+.documents-task-document-editor {
+  display: flex;
+  flex-direction: column;
+  min-height: 45dvh;
+  flex: 1;
+}
+
+.documents-task-document-editor .file-editor-container {
+  flex: 1;
+  min-height: 40dvh;
+}
+
 .documents-file-path-header {
   margin: 0;
   padding: var(--space-sm) var(--space-md);
@@ -318,19 +341,6 @@ Artifacts controls are the first page content below the shared header, so add a
   flex: 1;
 }
 
-/*
-FNXC:ArtifactsView 2026-07-10-16:10:
-Subtle view-only indicator for the project-file preview header; muted so it informs without competing with the Plain/Markdown toggle. Shared markup serves desktop and mobile.
-*/
-.documents-readonly-badge {
-  flex-shrink: 0;
-  color: var(--text-muted);
-  font-size: 11px;
-  text-transform: uppercase;
-  letter-spacing: 0.04em;
-  white-space: nowrap;
-}
-
 .documents-content-viewer-text {
   border: 1px solid var(--border);
   border-radius: var(--radius-md);
@@ -409,18 +419,15 @@ FN-7811 reuses the Project Files shell for Task Documents, while task-scoped sid
   border-left-color: transparent;
 }
 
-.documents-task-document-title-block {
-  display: flex;
-  flex: 1;
-  min-width: 0;
-  flex-direction: column;
-  gap: var(--space-xs);
-}
-
+/*
+FNXC:DocumentsView 2026-07-11-14:30:
+The meta line (author · revision · date) renders as its own row directly under the path+actions header row; the viewer column's gap is too tall between two related header rows, so the meta pulls itself closer to the path box it annotates.
+*/
 .documents-task-document-meta {
   padding: 0;
   border-bottom: none;
   flex-wrap: wrap;
+  margin-top: calc(-1 * var(--space-sm));
 }
 
 .documents-group-task-id {

packages/dashboard/app/components/DocumentsView.tsx

@@ -1,17 +1,18 @@
 import "./DocumentsView.css";
 import { useState, useMemo, useCallback, useEffect, useRef, type ChangeEvent } from "react";
 import { useTranslation } from "react-i18next";
-import { ArrowLeft, FileText, RefreshCw, Search, X, Eye, EyeOff } from "lucide-react";
+import { ArrowLeft, FileText, Pencil, RefreshCw, Search, X, Eye, EyeOff } from "lucide-react";
 import ReactMarkdown from "react-markdown";
 import remarkGfm from "remark-gfm";
 import type { ColumnId, TaskDocumentWithTask, TaskDetail } from "@fusion/core";
 import type { ToastType } from "../hooks/useToast";
-import { fetchTaskDetail, fetchWorkspaceFileContent, type MarkdownFileEntry } from "../api";
+import { fetchTaskDetail, fetchWorkspaceFileContent, putTaskDocument, saveWorkspaceFileContent, type MarkdownFileEntry } from "../api";
 import { useArtifacts } from "../hooks/useArtifacts";
 import { useDocuments } from "../hooks/useDocuments";
 import { useProjectMarkdownFiles } from "../hooks/useProjectMarkdownFiles";
 import { useSelectionComment } from "../hooks/useSelectionComment";
 import { SelectionCommentPopover } from "./SelectionCommentPopover";
+import { FileEditor } from "./FileEditor";
 import { LoadingSpinner } from "./LoadingSpinner";
 import { ArtifactsGallery } from "./ArtifactsGallery";
 import { ViewHeader } from "./ViewHeader";
@@ -73,8 +74,25 @@ export function DocumentsView({ projectId, addToast, onOpenDetail, onOpenArtifac
   const taskDocPlainPreviewRef = useRef<HTMLPreElement>(null);
   // Markdown render toggle for project file preview
   const [renderProjectMarkdown, setRenderProjectMarkdown] = useState(false);
-  // Markdown render toggles per task document card (scoped by doc ID)
+  /*
+  FNXC:DocumentsView 2026-07-11-14:45:
+  Markdown render toggles per task document card (scoped by doc ID). Operator requirement: task documents default to the RENDERED MARKDOWN view (not plain text) — the map only stores explicit toggles away from that default, so every `?? true` fallback here and in the toggle handler must stay in sync.
+  */
   const [taskDocMarkdownStates, setTaskDocMarkdownStates] = useState<Map<string, boolean>>(new Map());
+  /*
+  FNXC:DocumentsView 2026-07-11-13:40:
+  Operator requirement: task documents in the Artifacts view must be editable in place with the same CodeMirror FileEditor used for workspace files and artifact docs — the FN-7811 read-only pane is not enough. Editing state is scoped to the selected document ID so switching documents, tabs, or projects can never save a draft against the wrong document; the draft lives here (not in FileEditor) so Save can PUT it via putTaskDocument and refresh the SWR document list.
+  */
+  const [editingTaskDocumentId, setEditingTaskDocumentId] = useState<string | null>(null);
+  const [taskDocDraft, setTaskDocDraft] = useState("");
+  const [taskDocSaving, setTaskDocSaving] = useState(false);
+  /*
+  FNXC:DocumentsView 2026-07-11-14:45:
+  Operator requirement: Project Files must be editable in place too (same CodeMirror FileEditor), replacing the former Read-only badge contract. Saves go through the workspace file API for the "project" workspace and update the local preview content on success.
+  */
+  const [editingProjectFile, setEditingProjectFile] = useState(false);
+  const [projectFileDraft, setProjectFileDraft] = useState("");
+  const [projectFileSaving, setProjectFileSaving] = useState(false);
   const [selectionCommentOpen, setSelectionCommentOpen] = useState(false);
   const markdownSelection = useSelectionComment(markdownPreviewRef, { locked: selectionCommentOpen });
   const plainSelection = useSelectionComment(plainPreviewRef, { locked: selectionCommentOpen });
@@ -136,6 +154,12 @@ export function DocumentsView({ projectId, addToast, onOpenDetail, onOpenArtifac
     setFileLoading(false);
     setRenderProjectMarkdown(false);
     setTaskDocMarkdownStates(new Map());
+    setEditingTaskDocumentId(null);
+    setTaskDocDraft("");
+    setTaskDocSaving(false);
+    setEditingProjectFile(false);
+    setProjectFileDraft("");
+    setProjectFileSaving(false);
   }, [projectId]);
 
   const groupedDocuments = useMemo(() => {
@@ -225,6 +249,12 @@ export function DocumentsView({ projectId, addToast, onOpenDetail, onOpenArtifac
     setActiveTab(tab);
     if (tab !== "tasks") {
       setSelectedTaskDocumentId(null);
+      setEditingTaskDocumentId(null);
+      setTaskDocDraft("");
+    }
+    if (tab !== "project") {
+      setEditingProjectFile(false);
+      setProjectFileDraft("");
     }
   }, []);
 
@@ -258,6 +288,8 @@ export function DocumentsView({ projectId, addToast, onOpenDetail, onOpenArtifac
     setFileLoading(true);
     setFileError(null);
     setFileContent(null);
+    setEditingProjectFile(false);
+    setProjectFileDraft("");
 
     const requestId = requestIdRef.current + 1;
     requestIdRef.current = requestId;
@@ -288,25 +320,85 @@ export function DocumentsView({ projectId, addToast, onOpenDetail, onOpenArtifac
     setFileContent(null);
     setFileError(null);
     setFileLoading(false);
+    setEditingProjectFile(false);
+    setProjectFileDraft("");
   }, []);
 
+  const handleStartProjectFileEdit = useCallback(() => {
+    if (fileContent === null) return;
+    setProjectFileDraft(fileContent);
+    setEditingProjectFile(true);
+  }, [fileContent]);
+
+  const handleCancelProjectFileEdit = useCallback(() => {
+    setEditingProjectFile(false);
+    setProjectFileDraft("");
+  }, []);
+
+  const handleSaveProjectFileEdit = useCallback(async () => {
+    if (!selectedFile) return;
+    setProjectFileSaving(true);
+    try {
+      await saveWorkspaceFileContent("project", selectedFile.path, projectFileDraft, projectId);
+      setFileContent(projectFileDraft);
+      setEditingProjectFile(false);
+      setProjectFileDraft("");
+      addToast(t("documents.projectFileSaved", "File saved"), "success");
+    } catch (err) {
+      addToast(err instanceof Error ? err.message : String(err), "error");
+    } finally {
+      setProjectFileSaving(false);
+    }
+  }, [selectedFile, projectFileDraft, projectId, addToast, t]);
+
   const handleSelectTaskDocument = useCallback((docId: string) => {
     setSelectedTaskDocumentId(docId);
+    setEditingTaskDocumentId(null);
+    setTaskDocDraft("");
   }, []);
 
   const handleBackToTaskDocumentList = useCallback(() => {
     setSelectedTaskDocumentId(null);
+    setEditingTaskDocumentId(null);
+    setTaskDocDraft("");
   }, []);
 
   const handleToggleTaskDocMarkdown = useCallback((docId: string) => {
     setTaskDocMarkdownStates((prev) => {
       const next = new Map(prev);
-      const current = next.get(docId) ?? false;
+      const current = next.get(docId) ?? true;
       next.set(docId, !current);
       return next;
     });
   }, []);
 
+  const handleStartTaskDocEdit = useCallback(() => {
+    if (!selectedTaskDocument) return;
+    setTaskDocDraft(selectedTaskDocument.content);
+    setEditingTaskDocumentId(selectedTaskDocument.id);
+  }, [selectedTaskDocument]);
+
+  const handleCancelTaskDocEdit = useCallback(() => {
+    setEditingTaskDocumentId(null);
+    setTaskDocDraft("");
+  }, []);
+
+  const handleSaveTaskDocEdit = useCallback(async () => {
+    if (!selectedTaskDocument) return;
+    setTaskDocSaving(true);
+    try {
+      await putTaskDocument(selectedTaskDocument.taskId, selectedTaskDocument.key, taskDocDraft, {}, projectId);
+      await refreshDocuments();
+      setEditingTaskDocumentId(null);
+      setTaskDocDraft("");
+      addToast(t("documents.taskDocumentSaved", "Document saved"), "success");
+    } catch (err) {
+      addToast(err instanceof Error ? err.message : String(err), "error");
+    } finally {
+      setTaskDocSaving(false);
+    }
+  }, [selectedTaskDocument, taskDocDraft, projectId, refreshDocuments, addToast, t]);
+
   const activeError = activeTab === "project" ? projectFilesError : activeTab === "tasks" ? documentsError : artifactsError;
 
   const handleRetry = useCallback(async () => {
@@ -322,9 +414,10 @@ export function DocumentsView({ projectId, addToast, onOpenDetail, onOpenArtifac
   }, [activeTab, refreshArtifacts, refreshProjectFiles, refreshDocuments]);
 
   const activeCount = activeTab === "project" ? filteredProjectFiles.length : activeTab === "tasks" ? documents.length : artifacts.length;
-  const selectedTaskDocumentRendersMarkdown = selectedTaskDocument ? (taskDocMarkdownStates.get(selectedTaskDocument.id) ?? false) : false;
+  const selectedTaskDocumentRendersMarkdown = selectedTaskDocument ? (taskDocMarkdownStates.get(selectedTaskDocument.id) ?? true) : false;
   const activeTaskDocumentSelection = selectedTaskDocumentRendersMarkdown ? taskDocMarkdownSelection : taskDocPlainSelection;
-  const selectionPopover = activeTab === "project" && selectedFile && onSendSelectionToTask && activeProjectSelection ? (
+  const editingSelectedTaskDocument = selectedTaskDocument !== null && editingTaskDocumentId === selectedTaskDocument.id;
+  const selectionPopover = activeTab === "project" && selectedFile && !editingProjectFile && onSendSelectionToTask && activeProjectSelection ? (
     <SelectionCommentPopover
       selectedText={activeProjectSelection.selectedText}
       anchorRect={activeProjectSelection.anchorRect}
@@ -333,7 +426,7 @@ export function DocumentsView({ projectId, addToast, onOpenDetail, onOpenArtifac
       onOpenChange={setSelectionCommentOpen}
     />
   ) : null;
-  const taskDocumentSelectionPopover = activeTab === "tasks" && selectedTaskDocument && onSendSelectionToTask && activeTaskDocumentSelection ? (
+  const taskDocumentSelectionPopover = activeTab === "tasks" && selectedTaskDocument && !editingSelectedTaskDocument && onSendSelectionToTask && activeTaskDocumentSelection ? (
     <SelectionCommentPopover
       selectedText={activeTaskDocumentSelection.selectedText}
       anchorRect={activeTaskDocumentSelection.anchorRect}
@@ -516,29 +609,56 @@ export function DocumentsView({ projectId, addToast, onOpenDetail, onOpenArtifac
                       <div className="documents-content-header">
                         <p className="documents-file-path-header">{selectedFile.path}</p>
                         {/*
-                        FNXC:ArtifactsView 2026-07-10-16:10:
-                        First-run review feedback: the Artifacts preview pane did not communicate whether documents are editable. This pane is view-only (there is no editor here — editing happens elsewhere, e.g. the workspace FileEditor), so a persistent Read-only badge states that explicitly on both desktop and mobile. Select-to-comment still works and is the intended interaction.
+                        FNXC:DocumentsView 2026-07-11-14:45:
+                        Operator requirement: Project Files are editable in place with the shared CodeMirror FileEditor, replacing the former Read-only badge contract (the FN-7810-era badge said "editing happens elsewhere"; it now happens here). While editing, the Markdown/Plain toggle is replaced by Cancel/Save and select-to-comment is suppressed.
                         */}
-                        <span
-                          className="documents-readonly-badge badge"
-                          title={t("documents.readOnlyHint", "This preview is read-only. Select text to comment and send it to a new task.")}
-                        >
-                          {t("documents.readOnly", "Read-only")}
-                        </span>
-                        <button
-                          className="btn btn-sm document-mode-toggle"
-                          onClick={() => setRenderProjectMarkdown((prev) => !prev)}
-                          aria-label={renderProjectMarkdown ? t("documents.switchToPlainText", "Switch to plain text") : t("documents.switchToMarkdown", "Switch to markdown")}
-                          aria-pressed={renderProjectMarkdown}
-                          title={renderProjectMarkdown ? t("documents.switchToPlainText", "Switch to plain text") : t("documents.switchToMarkdown", "Switch to markdown")}
-                        >
-                          {renderProjectMarkdown ? t("documents.markdown", "Markdown") : t("documents.plain", "Plain")}
-                        </button>
+                        <div className="documents-task-document-actions">
+                          {editingProjectFile ? (
+                            <>
+                              <button className="btn btn-sm" onClick={handleCancelProjectFileEdit} disabled={projectFileSaving}>
+                                {t("documents.cancelEdit", "Cancel")}
+                              </button>
+                              <button className="btn btn-sm btn-primary" onClick={() => void handleSaveProjectFileEdit()} disabled={projectFileSaving}>
+                                {projectFileSaving ? t("documents.saving", "Saving…") : t("documents.saveProjectFile", "Save")}
+                              </button>
+                            </>
+                          ) : (
+                            <>
+                              <button
+                                className="btn btn-sm document-mode-toggle"
+                                onClick={() => setRenderProjectMarkdown((prev) => !prev)}
+                                aria-label={renderProjectMarkdown ? t("documents.switchToPlainText", "Switch to plain text") : t("documents.switchToMarkdown", "Switch to markdown")}
+                                aria-pressed={renderProjectMarkdown}
+                                title={renderProjectMarkdown ? t("documents.switchToPlainText", "Switch to plain text") : t("documents.switchToMarkdown", "Switch to markdown")}
+                              >
+                                {renderProjectMarkdown ? t("documents.markdown", "Markdown") : t("documents.plain", "Plain")}
+                              </button>
+                              <button
+                                className="btn btn-sm"
+                                onClick={handleStartProjectFileEdit}
+                                disabled={fileLoading || fileError !== null || fileContent === null}
+                                aria-label={t("documents.editProjectFile", "Edit project file")}
+                              >
+                                <Pencil size={14} aria-hidden="true" />
+                                {t("documents.edit", "Edit")}
+                              </button>
+                            </>
+                          )}
+                        </div>
                       </div>
                       {fileLoading ? (
                         <p className="documents-content-state"><LoadingSpinner label={t("documents.loadingFileContent", "Loading file content…")} /></p>
                       ) : fileError ? (
                         <p className="documents-content-state documents-content-state--error">{fileError}</p>
+                      ) : editingProjectFile ? (
+                        <div className="documents-task-document-editor" aria-label={t("documents.projectFileContentEditor", "Project file content editor")}>
+                          <FileEditor
+                            content={projectFileDraft}
+                            onChange={setProjectFileDraft}
+                            filePath={selectedFile.path}
+                            forceToolbarActionsVisible
+                          />
+                        </div>
                       ) : renderProjectMarkdown ? (
                         <div ref={markdownPreviewRef} className="documents-content-markdown">
                           <div className="markdown-body">
@@ -690,28 +810,62 @@ export function DocumentsView({ projectId, addToast, onOpenDetail, onOpenArtifac
                   </div>
                 ) : (
                   <div className="documents-content-viewer documents-task-document-viewer">
+                    {/*
+                    FNXC:DocumentsView 2026-07-11-14:30:
+                    The header actions (Plain/Edit, or Cancel/Save while editing) must sit on the same row as the document path box, vertically centered against it — when the path and the author/revision meta shared a title-block column, the actions centered on the two-row block and rendered visibly below the path box's midline (user-reported misalignment). The meta line now renders below the path+actions row at full width.
+                    */}
                     <div className="documents-content-header documents-task-document-header">
-                      <div className="documents-task-document-title-block">
-                        <p className="documents-file-path-header">{selectedTaskDocument.taskId} / {selectedTaskDocument.key}</p>
-                        <div className="document-card-meta documents-task-document-meta">
-                          <span className="document-card-author">{selectedTaskDocument.author}</span>
-                          <span className="document-card-separator">·</span>
-                          <span>{t("documents.revisionShort", "v{{revision}}", { revision: selectedTaskDocument.revision })}</span>
-                          <span className="document-card-separator">·</span>
-                          <span className="document-card-date">{formatTimestamp(selectedTaskDocument.updatedAt)}</span>
-                        </div>
+                      <p className="documents-file-path-header">{selectedTaskDocument.taskId} / {selectedTaskDocument.key}</p>
+                      {/*
+                      FNXC:DocumentsView 2026-07-11-13:40:
+                      Operator requirement: task documents must be editable in place from the Artifacts view with the shared CodeMirror FileEditor (not a plain textarea, and not read-only). While editing, the Markdown/Plain toggle is replaced by Cancel/Save (FileEditor carries its own Edit/Preview toolbar for markdown) and select-to-comment is suppressed so the composer lock cannot fight the editor selection.
+                      */}
+                      <div className="documents-task-document-actions">
+                        {editingSelectedTaskDocument ? (
+                          <>
+                            <button className="btn btn-sm" onClick={handleCancelTaskDocEdit} disabled={taskDocSaving}>
+                              {t("documents.cancelEdit", "Cancel")}
+                            </button>
+                            <button className="btn btn-sm btn-primary" onClick={() => void handleSaveTaskDocEdit()} disabled={taskDocSaving}>
+                              {taskDocSaving ? t("documents.saving", "Saving…") : t("documents.saveTaskDocument", "Save")}
+                            </button>
+                          </>
+                        ) : (
+                          <>
+                            <button
+                              className="btn btn-sm document-mode-toggle"
+                              onClick={() => handleToggleTaskDocMarkdown(selectedTaskDocument.id)}
+                              aria-label={selectedTaskDocumentRendersMarkdown ? t("documents.switchToPlainText", "Switch to plain text") : t("documents.switchToMarkdown", "Switch to markdown")}
+                              aria-pressed={selectedTaskDocumentRendersMarkdown}
+                              title={selectedTaskDocumentRendersMarkdown ? t("documents.switchToPlainText", "Switch to plain text") : t("documents.switchToMarkdown", "Switch to markdown")}
+                            >
+                              {selectedTaskDocumentRendersMarkdown ? t("documents.markdown", "Markdown") : t("documents.plain", "Plain")}
+                            </button>
+                            <button className="btn btn-sm" onClick={handleStartTaskDocEdit} aria-label={t("documents.editTaskDocument", "Edit task document")}>
+                              <Pencil size={14} aria-hidden="true" />
+                              {t("documents.edit", "Edit")}
+                            </button>
+                          </>
+                        )}
                       </div>
-                      <button
-                        className="btn btn-sm document-mode-toggle"
-                        onClick={() => handleToggleTaskDocMarkdown(selectedTaskDocument.id)}
-                        aria-label={selectedTaskDocumentRendersMarkdown ? t("documents.switchToPlainText", "Switch to plain text") : t("documents.switchToMarkdown", "Switch to markdown")}
-                        aria-pressed={selectedTaskDocumentRendersMarkdown}
-                        title={selectedTaskDocumentRendersMarkdown ? t("documents.switchToPlainText", "Switch to plain text") : t("documents.switchToMarkdown", "Switch to markdown")}
-                      >
-                        {selectedTaskDocumentRendersMarkdown ? t("documents.markdown", "Markdown") : t("documents.plain", "Plain")}
-                      </button>
                     </div>
-                    {selectedTaskDocumentRendersMarkdown ? (
+                    <div className="document-card-meta documents-task-document-meta">
+                      <span className="document-card-author">{selectedTaskDocument.author}</span>
+                      <span className="document-card-separator">·</span>
+                      <span>{t("documents.revisionShort", "v{{revision}}", { revision: selectedTaskDocument.revision })}</span>
+                      <span className="document-card-separator">·</span>
+                      <span className="document-card-date">{formatTimestamp(selectedTaskDocument.updatedAt)}</span>
+                    </div>
+                    {editingSelectedTaskDocument ? (
+                      <div className="documents-task-document-editor" aria-label={t("documents.taskDocumentContentEditor", "Task document content editor")}>
+                        <FileEditor
+                          content={taskDocDraft}
+                          onChange={setTaskDocDraft}
+                          filePath={selectedTaskDocument.key.includes(".") ? selectedTaskDocument.key : `${selectedTaskDocument.key}.md`}
+                          forceToolbarActionsVisible
+                        />
+                      </div>
+                    ) : selectedTaskDocumentRendersMarkdown ? (
                       <div ref={taskDocMarkdownPreviewRef} className="documents-content-markdown">
                         <div className="markdown-body">
                           <ReactMarkdown remarkPlugins={[remarkGfm]}>{selectedTaskDocument.content}</ReactMarkdown>

packages/dashboard/app/components/SelectionCommentPopover.css

@@ -25,8 +25,16 @@ Every :active override here must restate the positioning translate alongside the
 feedback so the trigger stays under the cursor for the whole press. This one shared rule
 covers all popover surfaces: DocumentsView project-file preview (plain and markdown) and
 FileEditor (editor and preview), desktop and mobile.
+
+FNXC:ArtifactsView 2026-07-11-14:20:
+Regression: `.selection-comment-trigger:active` and the global `.btn:active` are both
+specificity (0,2,0), so this fix silently lost to `.btn:active` when the CSS bundle order
+flipped and the mid-press teleport/no-op came back (same bundle-order failure mode the
+`.selection-comment-panel.card` rule below documents). `.btn.selection-comment-trigger:active`
+is (0,3,0) so the positioning translate wins regardless of bundle order. Never rely on
+source order against `.btn:active` here.
 */
-.selection-comment-trigger:active {
+.btn.selection-comment-trigger:active {
   transform: translate(-50%, calc(-1 * var(--space-xl))) scale(0.97);
 }
 
@@ -108,8 +116,9 @@ a selection near the bottom of the viewport from pushing the composer off-screen
   Mobile uses a taller lift, so its :active rule must restate the mobile translate too —
   otherwise the desktop :active rule (space-xl) would snap the pressed trigger to the
   desktop offset and reintroduce the missed-click no-op on touch/landscape-phone widths.
+  FNXC:ArtifactsView 2026-07-11-14:20: `.btn.` prefix for bundle-order immunity — see the desktop rule above.
   */
-  .selection-comment-trigger:active {
+  .btn.selection-comment-trigger:active {
     transform: translate(-50%, calc(-1 * var(--space-2xl))) scale(0.97);
   }
 

packages/dashboard/app/components/__tests__/DocumentsView.test.tsx

@@ -2,7 +2,7 @@ import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
 import { render, screen, fireEvent, waitFor, within } from "@testing-library/react";
 import type { ArtifactWithTask, TaskDocumentWithTask, TaskDetail } from "@fusion/core";
 import { DocumentsView } from "../DocumentsView";
-import { fetchArtifact, fetchTaskDetail, fetchWorkspaceFileContent, updateArtifact } from "../../api";
+import { fetchArtifact, fetchTaskDetail, fetchWorkspaceFileContent, putTaskDocument, saveWorkspaceFileContent, updateArtifact } from "../../api";
 import { useArtifacts } from "../../hooks/useArtifacts";
 import { useDocuments } from "../../hooks/useDocuments";
 import { useProjectMarkdownFiles } from "../../hooks/useProjectMarkdownFiles";
@@ -15,6 +15,8 @@ vi.mock("../../api", () => ({
   fetchArtifacts: vi.fn(),
   fetchArtifact: vi.fn(),
   updateArtifact: vi.fn(),
+  putTaskDocument: vi.fn(),
+  saveWorkspaceFileContent: vi.fn(),
   artifactMediaUrl: vi.fn((id: string) => `/api/artifacts/${id}/media`),
 }));
 
@@ -47,6 +49,8 @@ const mockFetchWorkspaceFileContent = vi.mocked(fetchWorkspaceFileContent);
 const mockFetchTaskDetail = vi.mocked(fetchTaskDetail);
 const mockFetchArtifact = vi.mocked(fetchArtifact);
 const mockUpdateArtifact = vi.mocked(updateArtifact);
+const mockPutTaskDocument = vi.mocked(putTaskDocument);
+const mockSaveWorkspaceFileContent = vi.mocked(saveWorkspaceFileContent);
 
 function mockSelectionRect() {
   const rect = new DOMRect(10, 20, 80, 12);
@@ -775,23 +779,48 @@ describe("DocumentsView", () => {
   });
 
   /*
-  FNXC:ArtifactsView 2026-07-10-16:20:
-  First-run review: the preview pane did not communicate that it is view-only. The Read-only
-  badge must render with the preview header in BOTH render modes (plain and markdown) — the
-  header markup is shared between desktop and mobile layouts.
+  FNXC:DocumentsView 2026-07-11-14:45:
+  Operator requirement: Project Files are editable in place with the shared CodeMirror FileEditor (this replaced the former Read-only badge contract). Edit swaps the preview for the editor, Save persists via the "project" workspace file API and updates the preview, Cancel discards without saving, and select-to-comment is suppressed while editing.
   */
-  it("shows a Read-only badge in the project file preview header in plain and markdown modes", async () => {
+  it("edits a project file in the shared file editor and saves via the workspace file API", async () => {
+    mockSaveWorkspaceFileContent.mockResolvedValue({ success: true } as Awaited<ReturnType<typeof saveWorkspaceFileContent>>);
     render(<DocumentsView addToast={addToast} onOpenDetail={onOpenDetail} />);
     // Landing tab is now Artifacts; these tests exercise the Project Files tab explicitly.
     fireEvent.click(screen.getByRole("tab", { name: /show project markdown files/i }));
 
     fireEvent.click(screen.getByRole("button", { name: "Open README.md" }));
     await screen.findByText(/Hello docs/);
-    expect(screen.getByText("Read-only")).toBeInTheDocument();
+    expect(screen.queryByText("Read-only")).not.toBeInTheDocument();
 
-    fireEvent.click(screen.getByRole("button", { name: /switch to markdown/i }));
-    await screen.findByText("Hello docs");
-    expect(screen.getByText("Read-only")).toBeInTheDocument();
+    fireEvent.click(screen.getByRole("button", { name: /edit project file/i }));
+    const editor = screen.getByLabelText("file editor");
+    expect(editor).toHaveValue("# README\nHello docs");
+    fireEvent.change(editor, { target: { value: "# README\nUpdated docs" } });
+    fireEvent.click(screen.getByRole("button", { name: "Save" }));
+
+    await waitFor(() => {
+      expect(mockSaveWorkspaceFileContent).toHaveBeenCalledWith("project", "README.md", "# README\nUpdated docs", undefined);
+    });
+    await waitFor(() => {
+      expect(screen.queryByLabelText("file editor")).not.toBeInTheDocument();
+    });
+    expect(screen.getByText(/Updated docs/)).toBeInTheDocument();
+  });
+
+  it("cancels project file editing without saving", async () => {
+    render(<DocumentsView addToast={addToast} onOpenDetail={onOpenDetail} />);
+    fireEvent.click(screen.getByRole("tab", { name: /show project markdown files/i }));
+
+    fireEvent.click(screen.getByRole("button", { name: "Open README.md" }));
+    await screen.findByText(/Hello docs/);
+
+    fireEvent.click(screen.getByRole("button", { name: /edit project file/i }));
+    fireEvent.change(screen.getByLabelText("file editor"), { target: { value: "Discarded" } });
+    fireEvent.click(screen.getByRole("button", { name: "Cancel" }));
+
+    expect(mockSaveWorkspaceFileContent).not.toHaveBeenCalled();
+    expect(screen.queryByLabelText("file editor")).not.toBeInTheDocument();
+    expect(screen.getByText(/Hello docs/)).toBeInTheDocument();
   });
 
   it("sends selected plain project file preview text to a new task description", async () => {
@@ -847,6 +876,8 @@ describe("DocumentsView", () => {
 
     fireEvent.click(screen.getByRole("tab", { name: /show task documents/i }));
     fireEvent.click(screen.getByRole("button", { name: "Open KB-001 plan" }));
+    // Markdown is the default render mode; switch to plain to exercise the plain-preview selection surface.
+    fireEvent.click(screen.getByRole("button", { name: /switch to plain text/i }));
     const plainPreview = screen.getByText("Alpha document content");
     selectNodeText(plainPreview);
 
@@ -866,7 +897,7 @@ describe("DocumentsView", () => {
 
     fireEvent.click(screen.getByRole("tab", { name: /show task documents/i }));
     fireEvent.click(screen.getByRole("button", { name: "Open KB-001 plan" }));
-    fireEvent.click(screen.getByRole("button", { name: /switch to markdown/i }));
+    // Markdown is the default render mode — no toggle needed.
     const markdownPreviewText = await screen.findByText("Alpha document content");
     selectNodeText(markdownPreviewText);
 
@@ -928,6 +959,53 @@ describe("DocumentsView", () => {
     expect(await screen.findByRole("button", { name: /add a comment/i })).toBeInTheDocument();
   });
 
+  /*
+  FNXC:DocumentsView 2026-07-11-13:40:
+  Operator requirement: task documents must be editable in place from the Artifacts view with the shared CodeMirror FileEditor. Surface enumeration for the affordance: Edit swaps the preview for the editor, Save persists via putTaskDocument and refreshes the list, Cancel restores the read view without saving, and select-to-comment is suppressed while editing so the composer cannot fight the editor selection.
+  */
+  it("edits a task document in the shared file editor and saves via putTaskDocument", async () => {
+    mockPutTaskDocument.mockResolvedValue(mockTaskDocuments[0]);
+    render(<DocumentsView addToast={addToast} onOpenDetail={onOpenDetail} />);
+
+    fireEvent.click(screen.getByRole("tab", { name: /show task documents/i }));
+    fireEvent.click(screen.getByRole("button", { name: "Open KB-001 plan" }));
+    fireEvent.click(screen.getByRole("button", { name: /edit task document/i }));
+
+    const editor = screen.getByLabelText("file editor");
+    expect(editor).toHaveValue("Alpha document content");
+    fireEvent.change(editor, { target: { value: "Updated document content" } });
+    fireEvent.click(screen.getByRole("button", { name: "Save" }));
+
+    await waitFor(() => {
+      expect(mockPutTaskDocument).toHaveBeenCalledWith("KB-001", "plan", "Updated document content", {}, undefined);
+    });
+    await waitFor(() => {
+      expect(screen.queryByLabelText("file editor")).not.toBeInTheDocument();
+    });
+    expect(addToast).toHaveBeenCalledWith("Document saved", "success");
+  });
+
+  it("cancels task document editing without saving and suppresses select-to-comment while editing", async () => {
+    mockSelectionRect();
+    const onSendSelectionToTask = vi.fn();
+    render(<DocumentsView addToast={addToast} onOpenDetail={onOpenDetail} onSendSelectionToTask={onSendSelectionToTask} />);
+
+    fireEvent.click(screen.getByRole("tab", { name: /show task documents/i }));
+    fireEvent.click(screen.getByRole("button", { name: "Open KB-001 plan" }));
+    selectNodeText(screen.getByText("Alpha document content"));
+    expect(await screen.findByRole("button", { name: /add a comment/i })).toBeInTheDocument();
+
+    fireEvent.click(screen.getByRole("button", { name: /edit task document/i }));
+    expect(screen.queryByRole("button", { name: /add a comment/i })).not.toBeInTheDocument();
+
+    fireEvent.change(screen.getByLabelText("file editor"), { target: { value: "Discarded draft" } });
+    fireEvent.click(screen.getByRole("button", { name: "Cancel" }));
+
+    expect(mockPutTaskDocument).not.toHaveBeenCalled();
+    expect(screen.queryByLabelText("file editor")).not.toBeInTheDocument();
+    expect(screen.getByText("Alpha document content")).toBeInTheDocument();
+  });
+
   it("search filters task documents and clears filtered-out selection", async () => {
     mockUseProjectMarkdownFiles.mockReturnValue({
       files: [],
@@ -1192,15 +1270,15 @@ describe("DocumentsView", () => {
 
     fireEvent.click(screen.getByRole("button", { name: "Open KB-001 plan" }));
 
-    // Task document toggle should default to raw (not influenced by project toggle)
-    const taskToggle = screen.getByRole("button", { name: /switch to markdown/i });
-    expect(taskToggle).toHaveAttribute("aria-pressed", "false");
+    // Task document toggle defaults to markdown (its own default, not influenced by project toggle)
+    const taskToggle = screen.getByRole("button", { name: /switch to plain text/i });
+    expect(taskToggle).toHaveAttribute("aria-pressed", "true");
 
-    // Toggle task document
+    // Toggle task document to plain
     fireEvent.click(taskToggle);
-    expect(screen.getByRole("button", { name: /switch to plain text/i })).toHaveAttribute("aria-pressed", "true");
+    expect(screen.getByRole("button", { name: /switch to markdown/i })).toHaveAttribute("aria-pressed", "false");
 
-    // Switch back to project - project toggle should still be on
+    // Switch back to project - project toggle should still be on markdown
     fireEvent.click(screen.getByRole("tab", { name: /show project markdown files/i }));
     expect(screen.getByRole("button", { name: /switch to plain text/i })).toHaveAttribute("aria-pressed", "true");
   });
@@ -1220,15 +1298,15 @@ describe("DocumentsView", () => {
 
     fireEvent.click(screen.getByRole("button", { name: "Open KB-001 plan" }));
 
-    // Should show raw text by default
+    // FNXC:DocumentsView 2026-07-11-14:45: operator requirement — task documents render markdown by default.
     expect(screen.getByText("Alpha document content")).toBeInTheDocument();
+    const toggleBtn = screen.getByRole("button", { name: /switch to plain text/i });
+    expect(toggleBtn).toHaveAttribute("aria-pressed", "true");
 
-    // Toggle should exist
-    const toggleBtn = screen.getByRole("button", { name: /switch to markdown/i });
-    expect(toggleBtn).toHaveAttribute("aria-pressed", "false");
-
-    // Click to toggle to markdown mode
+    // Click to toggle to plain mode and back
     fireEvent.click(toggleBtn);
+    expect(screen.getByRole("button", { name: /switch to markdown/i })).toHaveAttribute("aria-pressed", "false");
+    fireEvent.click(screen.getByRole("button", { name: /switch to markdown/i }));
     expect(screen.getByRole("button", { name: /switch to plain text/i })).toHaveAttribute("aria-pressed", "true");
   });
 });

packages/dashboard/app/components/__tests__/SelectionCommentPopover.test.tsx

@@ -77,6 +77,12 @@ describe("SelectionCommentPopover", () => {
   must include the `translate(-50%` positioning component. The popover is shared by
   DocumentsView (plain + markdown preview) and FileEditor (editor + preview), so this one
   stylesheet invariant covers all surfaces.
+
+  FNXC:ArtifactsView 2026-07-11-14:20:
+  The bug regressed a second way: `.selection-comment-trigger:active` ties `.btn:active` at
+  specificity (0,2,0), so a CSS bundle-order flip let `.btn:active` win again and the no-op
+  came back. Every :active trigger rule must now carry the `.btn.` prefix ((0,3,0)) so it
+  out-specifies `.btn:active` regardless of bundle order — asserted below.
   */
   it("keeps the positioning translate in every trigger transform, including :active press state", () => {
     const css = readFileSync(join(__dirname, "..", "SelectionCommentPopover.css"), "utf8");
@@ -87,7 +93,7 @@ describe("SelectionCommentPopover", () => {
     const rulePattern = /([^{}]+)\{([^{}]*)\}/g;
     for (const match of uncommented.matchAll(rulePattern)) {
       const selector = match[1].trim();
-      if (selector.split(",").some((part) => part.trim().startsWith(".selection-comment-trigger"))) {
+      if (selector.split(",").some((part) => part.trim().includes(".selection-comment-trigger"))) {
         triggerBlocks.push({ selector, block: match[2] });
       }
     }
@@ -102,6 +108,13 @@ describe("SelectionCommentPopover", () => {
 
     const activeBlocks = transformBlocks.filter(({ selector }) => selector.includes(":active"));
     expect(activeBlocks.length, "both desktop and mobile need an :active override that restates the translate").toBeGreaterThanOrEqual(2);
+
+    for (const { selector } of activeBlocks) {
+      expect(
+        selector.includes(".btn.selection-comment-trigger"),
+        `":active" trigger rule "${selector}" must use the .btn. prefix to out-specify the global .btn:active regardless of CSS bundle order`,
+      ).toBe(true);
+    }
   });
 
   /*