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>

scripts/init-db.sql

@@ -164,6 +164,7 @@ CREATE TABLE IF NOT EXISTS discovered_repos (
     github_forks INTEGER DEFAULT 0,
     default_branch TEXT DEFAULT 'main',
     is_archived BOOLEAN DEFAULT FALSE,
+    is_blocked BOOLEAN NOT NULL DEFAULT FALSE,
     scan_error TEXT,
     created_at TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP NOT NULL,
     updated_at TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP NOT NULL
@@ -471,13 +472,17 @@ ALTER TABLE skills ADD COLUMN IF NOT EXISTS quality_score INTEGER;
 ALTER TABLE skills ADD COLUMN IF NOT EXISTS quality_details JSONB;
 ALTER TABLE skills ADD COLUMN IF NOT EXISTS skill_type TEXT;  -- 'standalone', 'project-bound', 'collection', 'aggregator'
 ALTER TABLE skills ADD COLUMN IF NOT EXISTS is_duplicate BOOLEAN DEFAULT FALSE;
+ALTER TABLE skills ADD COLUMN IF NOT EXISTS is_owner_claimed BOOLEAN NOT NULL DEFAULT FALSE;
 ALTER TABLE skills ADD COLUMN IF NOT EXISTS canonical_skill_id TEXT;  -- points to original if duplicate
 ALTER TABLE skills ADD COLUMN IF NOT EXISTS repo_skill_count INTEGER;  -- cached count of skills in repo
+ALTER TABLE discovered_repos ADD COLUMN IF NOT EXISTS is_blocked BOOLEAN NOT NULL DEFAULT FALSE;
 
 CREATE INDEX IF NOT EXISTS idx_skills_quality ON skills(quality_score DESC NULLS LAST);
 CREATE INDEX IF NOT EXISTS idx_skills_type ON skills(skill_type);
 CREATE INDEX IF NOT EXISTS idx_skills_duplicate ON skills(is_duplicate);
 CREATE INDEX IF NOT EXISTS idx_skills_content_hash ON skills(content_hash);
+CREATE INDEX IF NOT EXISTS idx_skills_owner_claimed ON skills(is_owner_claimed) WHERE is_owner_claimed = TRUE;
+CREATE INDEX IF NOT EXISTS idx_discovered_repos_blocked ON discovered_repos(is_blocked) WHERE is_blocked = TRUE;
 
 -- Review pipeline columns (Phase 4+5 - February 2026)
 ALTER TABLE skills ADD COLUMN IF NOT EXISTS review_status TEXT DEFAULT 'unreviewed';
@@ -557,6 +562,12 @@ CREATE INDEX IF NOT EXISTS idx_reviews_skill ON skill_reviews(skill_id);
 CREATE INDEX IF NOT EXISTS idx_reviews_score ON skill_reviews(ai_score);
 CREATE INDEX IF NOT EXISTS idx_reviews_blog ON skill_reviews(blog_worthy) WHERE blog_worthy = true;
 
+-- Stale skill detection (March 2026)
+ALTER TABLE skills ADD COLUMN IF NOT EXISTS is_stale BOOLEAN DEFAULT FALSE;
+ALTER TABLE skills ADD COLUMN IF NOT EXISTS stale_since TIMESTAMP WITH TIME ZONE;
+ALTER TABLE skills ADD COLUMN IF NOT EXISTS stale_check_count INTEGER DEFAULT 0;
+CREATE INDEX IF NOT EXISTS idx_skills_stale ON skills(is_stale) WHERE is_stale = TRUE;
+
 -- Grant permissions
 GRANT ALL PRIVILEGES ON ALL TABLES IN SCHEMA public TO postgres;
 GRANT ALL PRIVILEGES ON ALL SEQUENCES IN SCHEMA public TO postgres;