refactor: rename tablet marker to floating-window--tablet-viewport, add shell naming maps

The right-padding bug recurred three times because 'Task Detail modal' names ONE
surface with THREE shells and fixes kept landing in the wrong file. Disambiguate:

- Rename the just-introduced .floating-window--tablet marker to
  .floating-window--tablet-viewport and document the naming contract next to it:
  --tablet-viewport = viewport MODE classifies tablet (touch or not, styling
  surface); --touch-geometry = tablet AND touch (enlarged 44px targets only).
- Add SHELL NAMING MAP breadcrumbs at the top of TaskDetailModal.css and
  TerminalModal.css pointing inset/padding fixes at the FloatingWindow shell
  that tablet popups and floating terminals actually render through.

Comment wording deliberately avoids dot-prefixed class tokens because
FloatingWindow.test.tsx scans raw CSS (comments included) with selector regexes.

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

.changeset/tablet-floating-window-right-inset-and-drag.md

@@ -4,4 +4,4 @@
 
 summary: Fix uneven right padding on tablet task/terminal popups; drag the terminal from anywhere in its toolbar.
 category: fix
-dev: Tablet-mode FloatingWindows (`.floating-window--tablet`) zero the FN-8015 scrollbar gutter; GitHub-import detail compensates locally. Terminal tab-strip empty space now bubbles to the `.terminal-header` drag handle (`touch-action: none` on the tablet floating header supersedes the FN-8633 pan-x contract).
+dev: Tablet-mode FloatingWindows (`.floating-window--tablet-viewport`) zero the FN-8015 scrollbar gutter; GitHub-import detail compensates locally. Terminal tab-strip empty space now bubbles to the `.terminal-header` drag handle (`touch-action: none` on the tablet floating header supersedes the FN-8633 pan-x contract).

packages/dashboard/app/components/FloatingWindow.css

@@ -545,13 +545,13 @@ Tablet windows drop FN-8015's inline-end scrollbar gutter. On tablet the gutter
 too-big, uneven right border inside Task Detail popups and the floating terminal (the inner
 surfaces already carry their own symmetric padding), and the mouse conflict FN-8015 solves —
 grabbing a hosted scrollbar thumb versus the east resize hot zone — does not apply to touch
-input, which never grabs scrollbar thumbs. This keys on tablet MODE (`.floating-window--tablet`,
+input, which never grabs scrollbar thumbs. This keys on tablet MODE (`.floating-window--tablet-viewport`,
 set from `useViewportMode()`), not `--touch-geometry`, so a non-touch window at tablet widths
 gets the same symmetric inset the operator sees on an iPad. Desktop keeps the FN-8015 gutter.
 Callers that relied on the gutter as their right inset must compensate under the same class
 (see `.github-import-detail-panel`).
 */
-.floating-window--tablet .floating-window__body {
+.floating-window--tablet-viewport .floating-window__body {
   margin-inline-end: 0;
 }
 

packages/dashboard/app/components/FloatingWindow.tsx

@@ -233,15 +233,19 @@ export function FloatingWindow({
   */
   const hasTabletTouchGeometry = isTabletTouchViewport(viewportMode);
   /*
-  FNXC:ModalTouchGeometry 2026-08-01-03:48:
-  Tablet MODE (touch or not) is a distinct styling surface from touch geometry: a 900px
-  non-touch window classifies tablet without `--touch-geometry`, yet operators still see the
-  FN-8015 scrollbar gutter as an uneven right inset there (third recurrence of the Task Detail
-  right-padding bug — FN-8630/FN-8634 fixed only the `.modal-overlay` shells, while every
-  tablet task popup and floating terminal renders through THIS host). Expose the mode as a
-  class so FloatingWindow.css can zero the gutter for all tablet windows.
+  FNXC:ModalTouchGeometry 2026-08-01-04:23:
+  NAMING CONTRACT — FloatingWindow has two distinct tablet markers; do not conflate them:
+  - `floating-window--tablet-viewport`: the viewport MODE classifies as tablet (769-1024px
+    width OR a known 768px touch tablet), touch or not. Pure styling surface — currently the
+    FN-8015 gutter zeroing lives here.
+  - `floating-window--touch-geometry`: tablet AND touch-capable (`isTabletTouchViewport`) —
+    enlarged 44px drag/resize targets only.
+  A 900px non-touch window is `--tablet-viewport` but NOT `--touch-geometry`, and operators
+  still see the FN-8015 scrollbar gutter as an uneven right inset there (third recurrence of
+  the Task Detail right-padding bug — FN-8630/FN-8634 fixed only the `.modal-overlay` shells,
+  while every tablet task popup and floating terminal renders through THIS host).
   */
-  const isTabletMode = viewportMode === "tablet";
+  const isTabletViewportMode = viewportMode === "tablet";
   const initialGeometry = useRef<{ size: FloatingWindowSize; position: FloatingWindowPosition } | null>(null);
   /*
   FNXC:ModalGeometryPersistence 2026-07-16-00:40:
@@ -648,7 +652,7 @@ export function FloatingWindow({
     >
       <div
         ref={panelRef}
-        className={`floating-window${hideHeader ? " floating-window--headerless" : ""}${hasTabletTouchGeometry ? " floating-window--touch-geometry" : ""}${isTabletMode ? " floating-window--tablet" : ""}${className ? ` ${className}` : ""}`}
+        className={`floating-window${hideHeader ? " floating-window--headerless" : ""}${hasTabletTouchGeometry ? " floating-window--touch-geometry" : ""}${isTabletViewportMode ? " floating-window--tablet-viewport" : ""}${className ? ` ${className}` : ""}`}
         style={panelStyle}
         data-testid={`floating-window-${windowKey}`}
         onPointerDownCapture={bringToFront}

packages/dashboard/app/components/GitHubImportModal.css

@@ -329,11 +329,11 @@ Padding lives on the panel rather than the pane content so header, toast, and sc
 
 /*
 FNXC:GitHubImport 2026-08-01-03:48:
-Tablet windows zero the shared FN-8015 body gutter (`.floating-window--tablet .floating-window__body`
+Tablet windows zero the shared FN-8015 body gutter (`.floating-window--tablet-viewport .floating-window__body`
 in FloatingWindow.css) because it rendered as an uneven right border on tablet. This panel's right
 inset was supplied by that gutter, so restore it locally to keep the panel's insets symmetric.
 */
-.floating-window--tablet .github-import-detail-panel {
+.floating-window--tablet-viewport .github-import-detail-panel {
   padding-inline-end: var(--space-lg);
 }
 

packages/dashboard/app/components/TaskDetailModal.css

@@ -1,4 +1,15 @@
 /* === Detail Modal === */
+/*
+FNXC:TaskDetailLayout 2026-08-01-04:23:
+SHELL NAMING MAP — read before fixing any Task Detail inset/padding bug. "Task Detail modal"
+is ONE surface with THREE shells, and only one of them lives in this file's `.modal-overlay`
+rules: (1) the fixed desktop modal (`.modal-overlay` + `.modal.task-detail-modal`, this file),
+(2) the tablet popup and desktop pop-out (FloatingWindow.css — class floating-window--task-detail,
+whose shared body element owns the FN-8015 inline-end gutter and the tablet-viewport zeroing),
+and (3) the mobile full-screen sheet. The right-
+padding bug recurred across FN-8630, FN-8634, and the 2026-08-01 tablet fix precisely because
+fixes landed only in shell (1) while the reporter was looking at shell (2).
+*/
 .task-detail-content {
   display: flex;
   flex-direction: column;

packages/dashboard/app/components/TerminalModal.css

@@ -7,6 +7,14 @@ FN-6603 found that unicode-range scoping is not enough when the symbols face is
 
 FNXC:Terminal 2026-06-20-18:04:
 FN-6811 recurrence #6 tightened ownership of this scoped symbols face: every terminal surface that exposes the DOM glyph fallback must define the same ASCII-excluding @font-face in its own CSS chunk, and tests must check each CSS owner independently rather than relying on combined app CSS.
+
+FNXC:TerminalLayout 2026-08-01-04:23:
+SHELL NAMING MAP — the terminal renders through FIVE shells and only some live in this file:
+docked/below panels and the mobile sheet are plain `.modal`/host elements styled here, but the
+FLOATING pop-out wraps `terminalContent` in FloatingWindow (FloatingWindow.css), whose shared
+body element owns the FN-8015 inline-end gutter and the tablet-viewport zeroing. An
+inset/padding bug reported "on the terminal
+modal" in tablet view is almost certainly the FloatingWindow shell, not a rule in this file.
 */
 @font-face {
   font-family: "Fusion Terminal Nerd Font Symbols";

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

@@ -210,13 +210,13 @@ describe("FloatingWindow", () => {
     */
     const tabletBody = cssRuleContaining(
       floatingWindowCss,
-      ".floating-window--tablet .floating-window__body",
+      ".floating-window--tablet-viewport .floating-window__body",
       "margin-inline-end",
     );
     expect(tabletBody).toContain("margin-inline-end: 0;");
     const tabletGitHubImportPanel = cssRuleContaining(
       allAppCss,
-      ".floating-window--tablet .github-import-detail-panel",
+      ".floating-window--tablet-viewport .github-import-detail-panel",
       "padding-inline-end",
     );
     expect(tabletGitHubImportPanel).toContain("padding-inline-end: var(--space-lg);");
@@ -251,10 +251,10 @@ describe("FloatingWindow", () => {
   /*
   FNXC:ModalTouchGeometry 2026-08-01-03:48:
   Tablet MODE is its own styling marker, distinct from `--touch-geometry`: a non-touch window
-  at tablet widths must still receive `floating-window--tablet` so the FN-8015 gutter zeroing
+  at tablet widths must still receive `floating-window--tablet-viewport` so the FN-8015 gutter zeroing
   applies everywhere the app classifies the viewport as tablet.
   */
-  it("marks tablet-mode windows with floating-window--tablet even without touch", () => {
+  it("marks tablet-mode windows with floating-window--tablet-viewport even without touch", () => {
     vi.stubGlobal("matchMedia", vi.fn((query: string) => ({
       matches: query === "(min-width: 769px) and (max-width: 1024px)",
       media: query,
@@ -271,7 +271,7 @@ describe("FloatingWindow", () => {
       </FloatingWindow>
     );
     const panel = screen.getByTestId("floating-window-tablet-mode");
-    expect(panel.className).toContain("floating-window--tablet");
+    expect(panel.className).toContain("floating-window--tablet-viewport");
   });
 
   it("keeps task-detail long content clear of right handles while preserving short-content right-edge resize", () => {