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/proxy/server.py

@@ -513,6 +513,16 @@ def create_proxy_app(settings: Settings) -> FastAPI:
             return _gh_error_response(exc)
         return JSONResponse({"items": [_serialize(s) for s in items]})
 
+    @app.get("/gh/v1/search_issues")
+    async def search_issues(request: Request, repo: str, q: str, limit: int = 10) -> JSONResponse:
+        await _authenticate(request)
+        github: GitHubClient = request.app.state.github
+        try:
+            items = await github.search_issues(repo, q, limit=limit)
+        except GitHubError as exc:
+            return _gh_error_response(exc)
+        return JSONResponse({"items": [_serialize(s) for s in items]})
+
     @app.get("/gh/v1/comments")
     async def list_comments(request: Request, repo: str, number: int) -> JSONResponse:
         await _authenticate(request)