feat(FN-2901): merge fusion/fn-2901

- fix(FN-2901): reset source issue collapse state on task change
- fix(FN-2901): use issue number in collapsed source issue summary
- feat(FN-2901): complete Step 5 — finalize source issue toggle UX
- test(FN-2901): complete Step 4 — verify collapsible source issue behavior
- feat(FN-2901): complete Step 3 — style collapsible source issue header
- feat(FN-2901): complete Step 2 — add collapsible source issue section
- feat(FN-2901): complete Step 1 — update lucide imports
- feat(FN-2729): merge fusion/fn-2729
- fix(engine): prevent auto-merge cooldown loop on unresolvable conflicts
- feat(FN-2911): improve chat attachment compose and preview UX

Fusion-Task-Id: FN-2901

packages/cli/src/commands/dashboard-tui/__tests__/app.test.tsx

@@ -438,7 +438,7 @@ describe("Settings view", () => {
     await waitForFrameContains(lastFrame, "Remote");
     expect(lastFrame() ?? "").toContain("cloudflare");
 
-    stdin.write("\t");
+    stdin.write("\u001B[C");
     await new Promise((r) => setTimeout(r, 20));
     stdin.write("C");
     await new Promise((r) => setTimeout(r, 20));
@@ -470,9 +470,9 @@ describe("Settings view", () => {
 
     const { lastFrame, stdin, unmount } = render(renderDashboardAppNode(controller));
     await waitForFrameContains(lastFrame, "──── Remote ────");
-    stdin.write("\t");
-    await new Promise((r) => setTimeout(r, 20));
 
+    stdin.write("\u001B[C");
+    await new Promise((r) => setTimeout(r, 20));
     stdin.write("L");
     await waitForFrameContains(lastFrame, "TTL ms:");
     stdin.write("\r");
@@ -508,9 +508,8 @@ describe("Settings view", () => {
     controller.setInteractiveView("settings");
 
     const { lastFrame, stdin, unmount } = render(renderDashboardAppNode(controller));
-    stdin.write("\t");
+    stdin.write("\u001B[C");
     await new Promise((r) => setTimeout(r, 20));
-
     stdin.write("P");
     await waitForFrameContains(lastFrame, "Persistent token: tok_****");
     expect(regeneratePersistentToken).toHaveBeenCalledTimes(1);
@@ -531,9 +530,9 @@ describe("Settings view", () => {
 
     const { lastFrame, stdin, unmount } = render(renderDashboardAppNode(controller));
     await waitForFrameContains(lastFrame, "──── Remote ────");
-    stdin.write("\t");
-    await new Promise((r) => setTimeout(r, 20));
 
+    stdin.write("\u001B[C");
+    await new Promise((r) => setTimeout(r, 20));
     stdin.write("L");
     await waitForFrameContains(lastFrame, "TTL ms:");
     stdin.write("a");
@@ -559,7 +558,7 @@ describe("Settings view", () => {
     controller.setInteractiveView("settings");
 
     const { lastFrame, stdin, unmount } = render(renderDashboardAppNode(controller));
-    stdin.write("\t");
+    stdin.write("\u001B[C");
     await new Promise((r) => setTimeout(r, 20));
     stdin.write("K");
     await waitForFrameContains(lastFrame, "QR SVG returned by server.");

packages/dashboard/app/components/TaskDetailModal.css

@@ -251,6 +251,64 @@
   color: var(--text-muted);
 }
 
+.detail-source-header {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: var(--space-sm);
+}
+
+.detail-source-summary {
+  display: flex;
+  align-items: center;
+  gap: var(--space-xs);
+}
+
+.detail-source-label {
+  color: var(--text-muted);
+  font-weight: 500;
+}
+
+.detail-source-number {
+  color: var(--text);
+  font-family: var(--font-mono);
+}
+
+.detail-source-toggle {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  min-width: 36px;
+  min-height: 36px;
+  padding: var(--space-xs);
+  border: 0;
+  border-radius: var(--radius-sm);
+  background: transparent;
+  color: var(--text-muted);
+  cursor: pointer;
+  transition: background var(--transition-fast), color var(--transition-fast);
+}
+
+.detail-source-toggle:hover {
+  color: var(--text);
+  background: var(--card-hover);
+}
+
+.detail-source-toggle:focus-visible {
+  outline: none;
+  box-shadow: var(--focus-ring-strong);
+}
+
+.detail-source-chevron--expanded {
+  transform: rotate(90deg);
+}
+
+.detail-source-section .detail-source-grid {
+  margin-top: var(--space-md);
+  padding-top: var(--space-md);
+  border-top: 1px solid var(--border);
+}
+
 /* Agent Log tab: stretch to fill the remaining modal body height
    so the log viewer uses all available space above the action bar. */
 .detail-section--agent-log {
@@ -1544,6 +1602,14 @@
     grid-template-columns: 1fr;
   }
 
+  .detail-source-header {
+    align-items: flex-start;
+  }
+
+  .detail-source-summary {
+    flex-wrap: wrap;
+  }
+
   .detail-body {
     padding: 14px;
     overflow-x: hidden;

packages/dashboard/app/components/TaskDetailModal.tsx

@@ -1,6 +1,6 @@
 import "./TaskDetailModal.css";
 import { useCallback, useEffect, useMemo, useRef, useState } from "react";
-import { Pencil, Bot, X, ChevronDown } from "lucide-react";
+import { Pencil, Bot, X, ChevronDown, ChevronRight } from "lucide-react";
 import { useModalResizePersist } from "../hooks/useModalResizePersist";
 import { useOverlayDismiss } from "../hooks/useOverlayDismiss";
 import ReactMarkdown from "react-markdown";
@@ -359,6 +359,7 @@ export function TaskDetailModal({
   // Split-menu dropdown state for footer actions
   const [showMoveMenu, setShowMoveMenu] = useState(false);
   const [showActionsMenu, setShowActionsMenu] = useState(false);
+  const [sourceIssueExpanded, setSourceIssueExpanded] = useState(false);
   const moveMenuRef = useRef<HTMLDivElement>(null);
   const moveButtonRef = useRef<HTMLButtonElement>(null);
   const actionsMenuRef = useRef<HTMLDivElement>(null);
@@ -395,6 +396,7 @@ export function TaskDetailModal({
     setEditSourceIssueExternalId(task.sourceIssue?.externalIssueId ?? "");
     setEditSourceIssueUrl(task.sourceIssue?.url ?? "");
     setEditExecutionMode(normalizeExecutionModeValue(task.executionMode));
+    setSourceIssueExpanded(false);
     setIsEditing(false);
   }, [task.id, task.title, task.description, task.sourceIssue, task.executionMode]);
 
@@ -1695,38 +1697,68 @@ export function TaskDetailModal({
           <MergeDetails task={task} />
           {task.sourceIssue && (
             <div className="detail-section detail-source-section">
-              <h4>Source Issue</h4>
+              <div className="detail-source-header">
-              <dl className="detail-source-grid">
+                <div className="detail-source-summary">
-                <div>
+                  <span className="detail-source-label">Source issue</span>
-                  <dt>Provider</dt>
+                  {task.sourceIssue.url ? (
-                  <dd>{task.sourceIssue.provider}</dd>
+                    <a
+                      className="detail-source-link detail-source-number"
+                      href={task.sourceIssue.url}
+                      target="_blank"
+                      rel="noopener noreferrer"
+                    >
+                      {`(#${task.sourceIssue.issueNumber})`}
+                    </a>
+                  ) : (
+                    <span className="detail-source-number">{`(#${task.sourceIssue.issueNumber})`}</span>
+                  )}
                 </div>
-                <div>
+                <button
-                  <dt>Repository</dt>
+                  type="button"
-                  <dd>{task.sourceIssue.repository}</dd>
+                  className="detail-source-toggle"
-                </div>
+                  aria-expanded={sourceIssueExpanded}
-                <div>
+                  aria-label={sourceIssueExpanded ? "Collapse source issue details" : "Expand source issue details"}
-                  <dt>Issue Identifier</dt>
+                  onClick={() => setSourceIssueExpanded((expanded) => !expanded)}
-                  <dd>{task.sourceIssue.externalIssueId}</dd>
+                >
-                </div>
+                  <ChevronRight
-                <div>
+                    size={16}
-                  <dt>URL</dt>
+                    className={sourceIssueExpanded ? "detail-source-chevron--expanded" : undefined}
-                  <dd>
+                  />
-                    {task.sourceIssue.url ? (
+                </button>
-                      <a
+              </div>
-                        className="detail-source-link"
+              {sourceIssueExpanded && (
-                        href={task.sourceIssue.url}
+                <dl className="detail-source-grid">
-                        target="_blank"
+                  <div>
-                        rel="noopener noreferrer"
+                    <dt>Provider</dt>
-                      >
+                    <dd>{task.sourceIssue.provider}</dd>
-                        {task.sourceIssue.url}
+                  </div>
-                      </a>
+                  <div>
-                    ) : (
+                    <dt>Repository</dt>
-                      <span className="detail-source-empty">(none)</span>
+                    <dd>{task.sourceIssue.repository}</dd>
-                    )}
+                  </div>
-                  </dd>
+                  <div>
-                </div>
+                    <dt>Issue Identifier</dt>
-              </dl>
+                    <dd>{task.sourceIssue.externalIssueId}</dd>
+                  </div>
+                  <div>
+                    <dt>URL</dt>
+                    <dd>
+                      {task.sourceIssue.url ? (
+                        <a
+                          className="detail-source-link"
+                          href={task.sourceIssue.url}
+                          target="_blank"
+                          rel="noopener noreferrer"
+                        >
+                          {task.sourceIssue.url}
+                        </a>
+                      ) : (
+                        <span className="detail-source-empty">(none)</span>
+                      )}
+                    </dd>
+                  </div>
+                </dl>
+              )}
             </div>
           )}
           <div className="detail-section detail-agent-section">

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

@@ -48,7 +48,7 @@ vi.mock("lucide-react", () => ({
   MessageSquare: () => null,
   ChevronUp: () => null,
   ChevronDown: () => null,
-  ChevronRight: () => null,
+  ChevronRight: (props: any) => <svg data-testid="chevron-right-icon" {...props} />,
   X: () => null,
   Maximize2: () => null,
   Minimize2: () => null,
@@ -4193,7 +4193,8 @@ describe("TaskDetailModal", () => {
       vi.clearAllMocks();
     });
 
-    it("renders source issue fields and link in read mode", () => {
+    it("renders source issue collapsed by default and expands details on toggle", async () => {
+      const user = userEvent.setup();
       render(
         <TaskDetailModal
           task={makeTask({
@@ -4214,13 +4215,28 @@ describe("TaskDetailModal", () => {
         />,
       );
 
-      expect(screen.getByText("Source Issue")).toBeTruthy();
+      expect(screen.getByText("Source issue")).toBeTruthy();
+      expect(screen.getByRole("link", { name: "(#2473)" })).toHaveAttribute(
+        "href",
+        "https://github.com/runfusion/fusion/issues/2473",
+      );
+      expect(screen.queryByText("Provider")).toBeNull();
+
+      const toggle = screen.getByRole("button", { name: "Expand source issue details" });
+      expect(toggle).toHaveAttribute("aria-expanded", "false");
+      const chevron = screen.getByTestId("chevron-right-icon");
+      expect(chevron.classList.contains("detail-source-chevron--expanded")).toBe(false);
+
+      await user.click(toggle);
+
+      expect(screen.getByRole("button", { name: "Collapse source issue details" })).toHaveAttribute("aria-expanded", "true");
+      expect(screen.getByText("Provider")).toBeTruthy();
       expect(screen.getByText("github")).toBeTruthy();
       expect(screen.getByText("runfusion/fusion")).toBeTruthy();
-      expect(screen.getByText("I_kgDOExample")).toBeTruthy();
       const sourceLink = screen.getByRole("link", { name: "https://github.com/runfusion/fusion/issues/2473" });
       expect(sourceLink).toHaveAttribute("href", "https://github.com/runfusion/fusion/issues/2473");
       expect(sourceLink).toHaveAttribute("target", "_blank");
+      expect(screen.getByTestId("chevron-right-icon").classList.contains("detail-source-chevron--expanded")).toBe(true);
     });
 
     it("hides source issue read section when sourceIssue metadata is missing", () => {
@@ -4236,7 +4252,7 @@ describe("TaskDetailModal", () => {
         />,
       );
 
-      expect(screen.queryByText("Source Issue")).toBeNull();
+      expect(screen.queryByText("Source issue")).toBeNull();
       expect(screen.queryByText("No source issue metadata recorded.")).toBeNull();
     });