refactor(issue-sync): streamline issue closing logic and enhance error handling

backend/app/api/forgejo_issues.py

@@ -694,7 +694,10 @@ async def close_issue(
     if auth.user is None:
         raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED)
 
-    # Get boards linked to this issue's repository for this organization.
+    # Check board links — used for authorization and activity logging.
+    # If the repository is not linked to any board the user can still close
+    # the issue (org membership is sufficient); we just skip the board-scoped
+    # activity event.
     links = (
         await session.exec(
             select(BoardRepositoryLink).where(
@@ -703,12 +706,9 @@ async def close_issue(
             )
         )
     ).all()
-    if not links:
-        raise HTTPException(
-            status_code=status.HTTP_404_NOT_FOUND,
-            detail="Issue repository is not linked to any board",
-        )
 
+    authorized_board_id: object = None
+    if links:
         allowed_board_ids = set(await list_accessible_board_ids(session, member=ctx.member, write=True))
         authorized_board_id = next(
             (link.board_id for link in links if link.board_id in allowed_board_ids),
@@ -735,6 +735,7 @@ async def close_issue(
         raise HTTPException(status_code=status.HTTP_502_BAD_GATEWAY, detail=str(e))
 
     repository_full_name = str(result.get("repository_full_name") or "unknown/unknown")
+    if authorized_board_id is not None:
         record_activity(
             session,
             event_type="forgejo.issue.closed",