feat(ts-migration): Phase 3-4 — all components + tests JS→TS

Converted 11 remaining production files:
  - services/*.ts (toolsService, taskService, git-utils, storageService,
    adminService, gitService)
  - lib/auth/permissions.ts
  - lib/components/layout/sidebarNavigation.ts
  - lib/components/reports/reportTypeProfiles.ts
  - components/git/useGitManager.ts
  - routes/datasets/review/useReviewSession.ts
  - routes/datasets/review/review-workspace-helpers.ts
  - routes/settings/settings-utils.ts

All production files have proper GRACE contracts:
  - C2/C3 with @BRIEF, @PRE, @POST, @SIDE_EFFECT, @RELATION
  - Generic <T = unknown> for API calls
  - Typed interfaces for state/options

Phase 3: 126 .svelte components → <script lang="ts">
Phase 4: 53 test .js files → .ts

Final verification:
  - npm run build ✅
  - npm run test ✅ (66 passed, 6 pre-existing failures unchanged)

Total: 0 .js files remain in production code

frontend/src/components/git/GitMergeDialog.svelte

@@ -5,7 +5,7 @@
 <!-- @RELATION CALLS -> [EXT:frontend:gitService] -->
 <!-- @UX_STATE Open -> Dialog with merge context, status, and action buttons. -->
 <!-- @UX_STATE Loading -> Recovery state loading spinner. -->
-<script>
+<script lang="ts">
   import { t } from "$lib/i18n";
   import { Button } from "$lib/ui";