feat(frontend): slice 8 — remove MUI/@emotion deps + update REQUIREMENTS

Web UI rework. Final slice.
- Remove from package.json: @mui/material, @mui/icons-material,
  @mui/x-data-grid, @emotion/react, @emotion/styled (zero consumers
  remain in src after slices 1-7b; grep-verified).
- Update docs/REQUIREMENTS.md (+63 lines): single design system
  (shadcn/ui + Tailwind v4 + lucide-react), thin-dashboard observability
  model (no in-app charts; Grafana deep-links), TanStack tables
  (visibility-only parity), reconciled IA (Backups top-level nav;
  Media at /media with /applications redirect), repurposed chart-*
  status cues, removed deps list.
- Note: AGENTS.md 'node --test tests' invocation is a pre-existing
  broken command (treats tests/ as a module); correct form is
  'node --test' (auto-discover, 5/5 pass) — verified identical at
  pre-rework baseline ef5311b.

Gate: build + lint + vitest (23/64) + node --test (5/5) green.
Web UI rework complete.

openspec/changes/web-ui-rework/tasks.md

@@ -199,11 +199,11 @@ Each slice section restates this gate as its final task.
 
 ### Slice 6b — compose dialog, formatting actions, attachments
 
-- [ ] Migrate the compose dialog (`Dialog`/`DialogActions`/`DialogContent`/`DialogTitle` + `TextField`/`Divider`/`IconButton`) → shadcn `Dialog` family + `Input`/`Textarea`/`Separator` + `Button variant="ghost" size="icon"`.
-- [ ] Replace the 9 `@mui/icons-material` icons with lucide per design §5: `Close→X`, `AttachFile→Paperclip`, `FormatBold→Bold`, `FormatItalic→Italic`, `Link→Link`, `FormatListBulleted→List`, `MailOutlined→Mail`, `Send→Send`, `DeleteOutlined→Trash2`.
-- [ ] Preserve the rich-text compose behavior: subject + html body, markup insertion actions (bold/italic/link/list), file attachments (FormData), queue-status polling (`useUserMessageQueueStatus`), and send (`useSendUserMessage`).
-- [ ] Add component tests for selection toggle, drawer open, and at least one compose formatting action.
-- [ ] **Exit gate (6a+6b):** `UsersPage.impl.tsx` fully MUI/icon-MUI-free; drawer, selection-across-pages, and compose/send behavior preserved; `npm run build` + `npm run lint` + `npm test` + `node --test tests` green on each sub-PR.
+- [x] Migrate the compose dialog (`Dialog`/`DialogActions`/`DialogContent`/`DialogTitle` + `TextField`/`Divider`/`IconButton`) → shadcn `Dialog` family + `Input`/`Textarea`/`Separator` + `Button variant="ghost" size="icon"`.
+- [x] Replace the 9 `@mui/icons-material` icons with lucide per design §5: `Close→X`, `AttachFile→Paperclip`, `FormatBold→Bold`, `FormatItalic→Italic`, `Link→Link`, `FormatListBulleted→List`, `MailOutlined→Mail`, `Send→Send`, `DeleteOutlined→Trash2`.
+- [x] Preserve the rich-text compose behavior: subject + html body, markup insertion actions (bold/italic/link/list), file attachments (FormData), queue-status polling (`useUserMessageQueueStatus`), and send (`useSendUserMessage`).
+- [x] Add component tests for selection toggle, drawer open, and at least one compose formatting action.
+- [x] **Exit gate (6a+6b):** `UsersPage.impl.tsx` fully MUI/icon-MUI-free; drawer, selection-across-pages, and compose/send behavior preserved; `npm run build` + `npm run lint` + `npm test` + `node --test tests` green on each sub-PR.
 
 ---
 
@@ -239,13 +239,13 @@ Each slice section restates this gate as its final task.
 > ~80–160 lines, single PR. Depends on all prior slices. `@mui/*` + `@emotion/*` are
 > removed only after every consumer is gone.
 
-- [ ] Remove from `frontend/package.json`: `@mui/material`, `@mui/icons-material`, `@mui/x-data-grid`, `@emotion/react`, `@emotion/styled` (run `npm install`/regenerate the lockfile).
-- [ ] Grep-verify ZERO remaining imports: recursive search of `frontend/src` for `@mui/material`, `@mui/icons-material`, `@mui/x-data-grid`, `@emotion/react`, `@emotion/styled` returns no matches (hard gate for the spec "No MUI imports remain" scenario).
-- [ ] Grep-verify `recharts`, `d3`, `d3-*` have zero imports and are absent from `package.json` (carry-over from slice 1; re-confirm).
-- [ ] Confirm `frontend/src/theme.ts` does not exist and no `theme`/`getAppTheme` import remains.
-- [ ] Run final gates from `frontend/`: `npm run build` (tsc -b + vite build), `npm run lint`, `npm test`, and `node --test tests` — all green.
-- [ ] Update `docs/REQUIREMENTS.md` per `AGENTS.md`: document the single design system (shadcn/ui + Tailwind v4 + lucide-react), the thin-dashboard observability model (no in-app charts; Grafana deep-links), TanStack tables (visibility-only parity), the reconciled IA (Backups top-level nav; Media at `/media` with `/applications` redirect), the repurposed `chart-*` status cues, and the removal of `@mui/*`/`@emotion/*`/`recharts`/`d3`/`theme.ts`.
-- [ ] **Exit gate:** recursive search of `frontend/src` for `@mui/*` and `@emotion/*` returns zero; requirements doc updated; `npm run build` + `npm run lint` + `npm test` + `node --test tests` all green.
+- [x] Remove from `frontend/package.json`: `@mui/material`, `@mui/icons-material`, `@mui/x-data-grid`, `@emotion/react`, `@emotion/styled` (run `npm install`/regenerate the lockfile).
+- [x] Grep-verify ZERO remaining imports: recursive search of `frontend/src` for `@mui/material`, `@mui/icons-material`, `@mui/x-data-grid`, `@emotion/react`, `@emotion/styled` returns no matches (hard gate for the spec "No MUI imports remain" scenario).
+- [x] Grep-verify `recharts`, `d3`, `d3-*` have zero imports and are absent from `package.json` (carry-over from slice 1; re-confirm).
+- [x] Confirm `frontend/src/theme.ts` does not exist and no `theme`/`getAppTheme` import remains.
+- [x] Run final gates from `frontend/`: `npm run build` (tsc -b + vite build), `npm run lint`, `npm test`, and `node --test tests` — all green.
+- [x] Update `docs/REQUIREMENTS.md` per `AGENTS.md`: document the single design system (shadcn/ui + Tailwind v4 + lucide-react), the thin-dashboard observability model (no in-app charts; Grafana deep-links), TanStack tables (visibility-only parity), the reconciled IA (Backups top-level nav; Media at `/media` with `/applications` redirect), the repurposed `chart-*` status cues, and the removal of `@mui/*`/`@emotion/*`/`recharts`/`d3`/`theme.ts`.
+- [x] **Exit gate:** recursive search of `frontend/src` for `@mui/*` and `@emotion/*` returns zero; requirements doc updated; `npm run build` + `npm run lint` + `npm test` + `node --test tests` all green.
 
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