GetBlockedIssues was showing external deps as blocking even when they
were satisfied (had a closed issue with provides:capability label).
Added filterBlockedByExternalDeps() which:
- Collects all external refs from blocked issues
- Checks each with CheckExternalDeps() in batch
- Filters satisfied refs from BlockedBy lists
- Updates BlockedByCount accordingly
- Removes issues with no remaining blockers (unless status=blocked/deferred)
This matches the behavior of GetReadyWork which already filters by
external deps correctly.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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