Add temporal filtering capabilities for searches by git branch/revision
and repository index dates (since/until). Integrates with the refactored
QueryIR-based search architecture.
- Add gitRevision, since, until parameters to SearchOptions
- Implement temporal repo filtering by indexedAt field
- Add branch filtering via QueryIR wrapper
- Add search_commits MCP tool for commit-based searches
- Update list_repos with activeAfter/activeBefore filtering
- Add 88 new tests (all passing)
Signed-off-by: Wayne Sun <gsun@redhat.com>
