sync: stale skill detection, sentry filtering, claim removal, review improvements

Stale Detection:
- Detect skills removed/moved from GitHub (3 consecutive 404s threshold)
- Hide stale skills from browse/search, show warning banner on detail page
- Serve cached files with isStale flag when GitHub returns 404
- Add stale-check crawler command for batch verification
- CLI shows warning when installing stale skills from cache

Sentry & Error Handling:
- Filter browser extension errors and add denyUrls
- Anti-inflation measures and sentinel recalibration for curation

Claim & Removal:
- Enhanced ClaimForm with repo-level removal support
- Add repo-removal-request API endpoint with tests
- Improved owner page with bilingual content

Review Pipeline:
- Review version and reviewer tracking in submit API
- Source format filter for pending reviews
- Updated review tests

Other:
- Updated i18n strings (en/fa)
- BrowseFilters improvements
- Dockerfile updates

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/web/app/api/stats/route.ts

@@ -35,7 +35,7 @@ export async function GET(request: NextRequest) {
     }
 
     // Browse-ready filter: exclude duplicates (matches browseReadyFilter in queries.ts)
-    const browseReady = sql`${skills.isDuplicate} = false`;
+    const browseReady = sql`${skills.isDuplicate} = false AND ${skills.isStale} = false`;
 
     // Browse-ready skill stats (skills count + contributors)
     const statsResult = await db