- Switched issue and PR search handlers to `gh api /search/issues` with `is:issue`/`is:pr` queries.
- Added REST search response models and mapped issue/code/commit/repo payloads to normalized results.
- Updated code, commit, and repo search parsing to read `{items}` envelopes and convert snake_case fields.
- Fixed merged-PR output state by deriving it from `pull_request.merged_at` in test fixtures.
can1357