feat(robomp): added repo-scoped issue search to issue triage flow

- Added `search_issues` support to the GitHub backend and client, including `state_reason` and `is_pull_request` in issue summaries.
- Added the `gh_search_issues` host tool with repo-prefixed query handling, non-empty/restricted `repo:` validation, default and bounded `limit` values, and inbound issue filtering.
- Added proxy integration for issue search with a new `/gh/v1/search_issues` endpoint and matching proxy-client method/response parsing.
- Updated triage prompts to perform pre-`classify_issue` duplicate and already-fixed checks via search, and added tests for search query formatting, validation, and state-aware match rendering.

python/robomp/src/worker.py

@@ -198,7 +198,7 @@ def _ensure_agent_run_dir() -> None:
         return
     try:
         run_dir.mkdir(parents=True, exist_ok=True)
-        for root, dirs, files in os.walk(run_dir):
+        for root, _dirs, files in os.walk(run_dir):
             root_path = Path(root)
             os.chown(root_path, -1, gid)
             root_path.chmod(0o2770)