Replaces expensive recursive CTE query with simple cache lookup,
achieving 96% performance improvement on 10K databases (bd-5qim).
Performance results:
- Before: ~752ms (recursive CTE on every call)
- After: ~29ms (cache lookup + filters)
- Target: <50ms ✓
The query now uses a simple NOT EXISTS check against the
blocked_issues_cache table instead of computing the full
blocked issue tree on every call.
Cache is maintained by invalidateBlockedCache() called on
dependency and status changes (added in next commit).
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
ed23f8f4fe