fix: close stale PRs on Forgejo when pipeline DB marks them closed

Two code paths set status='closed' in the pipeline DB without calling
the Forgejo API to close the PR. This caused 50 ghost PRs to accumulate
on Forgejo (dashboard shows review backlog) while the pipeline considered
them done.

- evaluate.py: no-diff stale branch close now calls Forgejo PATCH
- merge.py: permanent conflict close now calls Forgejo PATCH

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

lib/evaluate.py

@@ -533,6 +533,7 @@ async def evaluate_pr(conn, pr_number: int, tier: str = None) -> dict:
     diff = await get_pr_diff(pr_number)
     if not diff:
         # Close PRs with no diff — stale branch, nothing to evaluate
+        await forgejo_api("PATCH", repo_path(f"pulls/{pr_number}"), {"state": "closed"})
         conn.execute("UPDATE prs SET status='closed', last_error='closed: no diff against main (stale branch)' WHERE number = ?", (pr_number,))
         return {"pr": pr_number, "skipped": True, "reason": "no_diff_closed"}
 

lib/merge.py

@@ -1771,6 +1771,7 @@ async def _handle_permanent_conflicts(conn) -> int:
             except Exception:
                 pass
 
+        await forgejo_api("PATCH", repo_path(f"pulls/{pr_number}"), {"state": "closed"})
         conn.execute(
             "UPDATE prs SET status = 'closed', last_error = 'conflict_permanent: closed + filed in archive' WHERE number = ?",
             (pr_number,),