feat(phase3): phase 7 - integration & polish

Fix all build/type/lint errors, write 46 new tests (222 total across
20 files), regenerate Prisma client, update seed with user preferences.
Fix SvelteSet usage, add {#each} keys, clean unused imports.

plans/phase-3-advanced-features/CONTEXT.md

@@ -1,7 +1,7 @@
 # Feature Context: Phase 3 — Advanced Features
 
 ## Current State
-Phase 2 is complete and merged. 176 tests, full build passes. Phase 3 in progress. Phase 1 (Import/Export), Phase 2 (Sparklines), and Phase 3 (User Theme Overrides) are complete.
+Phase 7 (Integration & Polish) is complete. 222 tests across 20 test files, full build passes, `npm run check` 0 errors, `npm run lint` 0 errors. All phases 1-7 are done.
 
 ### Phase 1 (Import/Export) Summary
 exportService, importService, admin API endpoints, ImportExportPanel UI, Zod validation schema, i18n EN/RU translations.
@@ -23,6 +23,13 @@ exportService, importService, admin API endpoints, ImportExportPanel UI, Zod val
 - Header user menu includes "Settings" link
 - i18n keys: `settings.title`, `settings.theme`, `settings.primary_color`, `settings.hue`, `settings.saturation`, `settings.background`, `settings.language`, `settings.save`, `settings.saving`, `settings.saved` (EN/RU)
 
+### Phase 7 (Integration & Polish) Summary
+- Prisma client regenerated with user preference fields
+- Fixed lint errors: SvelteSet for reactive Set in DiscoveryPanel, `{#each}` keys in DiscoveryPanel/SparklineChart, unused vars in ThemeCustomizer/AppWidget
+- 46 new tests: exportService (4), importService (9), discoveryService (10), preferences API (11), quick-add API (8), broadcastSync (4)
+- Seed script updated: user preferences on admin/regular user, quick-add style Wiki.js app
+- Final state: 222 tests, 0 build errors, 0 type errors, 0 lint errors
+
 ## Cross-Phase Dependencies
 - Phases 1-3 are independent (import/export, sparklines, user themes)
 - Phase 4 (PWA) is independent