feat(robomp): added local issue indexing and commit-search tool support

- Added `ROBOMP_ISSUE_INDEX_SYNC_SECONDS` configuration and lifecycle-managed issue indexing through startup/shutdown hooks.
- Added issue/PR index tables with FTS5 triggers plus upsert and keyword/filter search helpers for indexed records.
- Added GitHub backend/proxy support for `IssueIndexEntry` and issue-index page retrieval, including webhook ingestion and periodic watermark-driven sync.
- Updated `gh_search_issues` to prefer local index queries when synchronized and added `search_commits` host tool with query modes and validation.

python/robomp/src/github_client.py

@@ -122,6 +122,30 @@ class IssueSummary:
     is_pull_request: bool = False
 
 
+@dataclass(slots=True, frozen=True)
+class IssueIndexEntry:
+    """Full projection of an issue/PR for the local search index (includes body).
+
+    Produced by `GitHubClient.list_issue_index_entries` / webhook payloads and
+    stored verbatim in the orchestrator's `issue_index` table.
+    """
+
+    repo: str
+    number: int
+    is_pull_request: bool
+    title: str
+    body: str
+    state: str  # open | closed
+    state_reason: str  # completed | not_planned | reopened | ""
+    merged_at: str  # ISO timestamp for merged PRs; "" otherwise
+    author: str
+    labels: tuple[str, ...]
+    comments: int
+    created_at: str
+    updated_at: str
+    html_url: str
+
+
 @dataclass(slots=True, frozen=True)
 class ReactionInfo:
     """A reaction on an issue/comment.
@@ -359,6 +383,31 @@ class GitHubClient:
         items = (data or {}).get("items") or []
         return [_summary_from_item(repo, item) for item in items]
 
+    async def list_issue_index_entries(
+        self,
+        repo: str,
+        *,
+        since: str | None = None,
+        page: int = 1,
+        per_page: int = 100,
+    ) -> list[IssueIndexEntry]:
+        """One page of issues AND PRs (with bodies) for the local search index.
+
+        `since` is GitHub's ISO `updated_at` lower bound; omit for a full
+        backfill. Callers page from 1 until a short page comes back.
+        """
+        params: dict[str, Any] = {
+            "state": "all",
+            "per_page": max(1, min(int(per_page), 100)),
+            "page": max(1, int(page)),
+            "sort": "updated",
+            "direction": "asc",
+        }
+        if since:
+            params["since"] = since
+        data = await self.request("GET", f"/repos/{repo}/issues", params=params)
+        return [index_entry_from_issue_object(repo, item) for item in (data or [])]
+
     async def list_comments(self, repo: str, number: int) -> list[CommentInfo]:
         data = await self.request("GET", f"/repos/{repo}/issues/{number}/comments", params={"per_page": 100})
         return [_comment_from_payload(item) for item in (data or [])]
@@ -602,6 +651,60 @@ def _summary_from_item(repo: str, item: Mapping[str, Any]) -> IssueSummary:
     )
 
 
+def index_entry_from_issue_object(repo: str, item: Mapping[str, Any]) -> IssueIndexEntry:
+    """Build an `IssueIndexEntry` from a REST *issue-shaped* object.
+
+    Accepts both plain issues and the issue representation of a PR (webhook
+    `issues`/`issue_comment` payloads, `/repos/{repo}/issues` items): PRs carry
+    a `pull_request` sub-object holding `merged_at`.
+    """
+    user = item.get("user") or {}
+    labels_raw = item.get("labels") or []
+    pr_obj = item.get("pull_request")
+    is_pr = pr_obj is not None
+    merged_at = str(pr_obj.get("merged_at") or "") if isinstance(pr_obj, Mapping) else ""
+    return IssueIndexEntry(
+        repo=repo,
+        number=int(item["number"]),
+        is_pull_request=is_pr,
+        title=str(item.get("title") or ""),
+        body=str(item.get("body") or ""),
+        state=str(item.get("state") or "open"),
+        state_reason=str(item.get("state_reason") or ""),
+        merged_at=merged_at,
+        author=str(user.get("login") or ""),
+        labels=tuple(str(lbl["name"]) if isinstance(lbl, dict) else str(lbl) for lbl in labels_raw),
+        comments=int(item.get("comments") or 0),
+        created_at=str(item.get("created_at") or ""),
+        updated_at=str(item.get("updated_at") or ""),
+        html_url=str(item.get("html_url") or ""),
+    )
+
+
+def index_entry_from_pr_object(repo: str, item: Mapping[str, Any]) -> IssueIndexEntry:
+    """Build an `IssueIndexEntry` from a REST *pull-request-shaped* object
+    (webhook `pull_request*` payloads), where `merged_at` sits at the top level.
+    """
+    user = item.get("user") or {}
+    labels_raw = item.get("labels") or []
+    return IssueIndexEntry(
+        repo=repo,
+        number=int(item["number"]),
+        is_pull_request=True,
+        title=str(item.get("title") or ""),
+        body=str(item.get("body") or ""),
+        state=str(item.get("state") or "open"),
+        state_reason="",
+        merged_at=str(item.get("merged_at") or ""),
+        author=str(user.get("login") or ""),
+        labels=tuple(str(lbl["name"]) if isinstance(lbl, dict) else str(lbl) for lbl in labels_raw),
+        comments=int(item.get("comments") or 0),
+        created_at=str(item.get("created_at") or ""),
+        updated_at=str(item.get("updated_at") or ""),
+        html_url=str(item.get("html_url") or ""),
+    )
+
+
 def _pr_file_from_payload(data: Mapping[str, Any]) -> PullRequestFileInfo:
     return PullRequestFileInfo(
         path=str(data.get("filename") or data.get("path") or ""),
@@ -663,6 +766,7 @@ __all__ = [
     "CommentInfo",
     "GitHubClient",
     "GitHubError",
+    "IssueIndexEntry",
     "IssueInfo",
     "IssueSummary",
     "PullRequestFileInfo",
@@ -671,5 +775,7 @@ __all__ = [
     "ReactionInfo",
     "RepoInfo",
     "ReviewCommentInfo",
+    "index_entry_from_issue_object",
+    "index_entry_from_pr_object",
     "parse_issue_payload",
 ]