feat(robomp): added incoming PR review feature with classify and submit

- Added `review_pr` task that checks out PR head in a detached worktree, classifies rank/type/area, and posts a batched GitHub review as `event=COMMENT`.
- Added four new host tools: `fetch_pr`, `classify_pr`, `pr_review_comment`, and `submit_pr_review`; review tools self-gate on `review_mode`, push/open-PR tools refuse when `review_mode` is set.
- Added sqlite staging table `pr_review_comments` with `stage_review_comment`, `list_staged_review_comments`, and `clear_staged_review_comments` DAOs.
- Routed `pull_request.opened/reopened/ready_for_review` to `review_pr` and extended `pull_request.closed` cleanup to any tracked PR regardless of author.

python/robomp/src/github_backend.py

@@ -8,12 +8,14 @@ dataclasses (`IssueInfo`, `RepoInfo`, …) defined in `github_client`.
 
 from __future__ import annotations
 
-from typing import Protocol
+from collections.abc import Mapping
+from typing import Any, Protocol
 
 from robomp.github_client import (
     CommentInfo,
     IssueInfo,
     IssueSummary,
+    PullRequestFileInfo,
     PullRequestInfo,
     PullRequestReviewInfo,
     ReactionInfo,
@@ -34,6 +36,8 @@ class GitHubBackend(Protocol):
 
     async def get_pull_request(self, repo: str, number: int) -> PullRequestInfo: ...
 
+    async def list_pr_files(self, repo: str, pr_number: int) -> list[PullRequestFileInfo]: ...
+
     async def list_issues(
         self,
         repo: str,
@@ -76,6 +80,16 @@ class GitHubBackend(Protocol):
 
     async def add_issue_labels(self, repo: str, number: int, labels: list[str]) -> tuple[str, ...]: ...
 
+    async def submit_pr_review(
+        self,
+        *,
+        repo: str,
+        pr_number: int,
+        body: str,
+        event: str,
+        comments: list[Mapping[str, Any]],
+    ) -> PullRequestReviewInfo: ...
+
     async def add_assignees(self, repo: str, number: int, assignees: list[str]) -> None: ...
 
     async def list_comment_reactions(self, repo: str, comment_id: int) -> tuple[ReactionInfo, ...]: ...