feat(agent-office): drop daily realestate cron + bookmark callback routing

- scheduler.py: remove _run_realestate_schedule() and its 09:15 cron job
- service_proxy.py: add realestate_bookmark_toggle() helper (PATCH bookmark endpoint)
- webhook.py: add _handle_realestate_bookmark() dispatcher before DB-lookup path;
  realestate_bookmark_{id} callbacks are handled inline without a DB entry
- tests/test_realestate_callback.py: 4 new unit tests covering happy path,
  invalid id, proxy error, and regression that approve/reject still uses DB path

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

agent-office/app/service_proxy.py

@@ -133,6 +133,16 @@ async def realestate_mark_read(match_id: int) -> Dict[str, Any]:
     return resp.json()
 
 
+async def realestate_bookmark_toggle(announcement_id: int) -> Dict[str, Any]:
+    """realestate-lab의 PATCH /api/realestate/announcements/{id}/bookmark 호출."""
+    async with httpx.AsyncClient(timeout=10) as client:
+        resp = await client.patch(
+            f"{REALESTATE_LAB_URL}/api/realestate/announcements/{announcement_id}/bookmark"
+        )
+        resp.raise_for_status()
+        return resp.json()
+
+
 # --- lotto-backend ---
 
 async def lotto_candidates(n: int = 20) -> Dict[str, Any]: