Fix clear-data to actually delete run_cache entries

- discard_run now deletes from run_cache and pending_runs tables
- Add delete_run_cache() and delete_pending_run() database functions
- Previously clear-data only cleared Redis, leaving DB cache intact

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/services/run_service.py

@@ -482,8 +482,18 @@ class RunService:
         # Remove task_id mapping from Redis
         self.redis.delete(f"{self.task_key_prefix}{run_id}")
 
-        # Note: We don't delete from run_cache as that's a permanent record
-        # of completed work. The content itself remains in cache.
+        # Remove from run_cache database table
+        try:
+            await self.db.delete_run_cache(run_id)
+        except Exception as e:
+            import logging
+            logging.getLogger(__name__).warning(f"Failed to delete run_cache for {run_id}: {e}")
+
+        # Remove pending run if exists
+        try:
+            await self.db.delete_pending_run(run_id)
+        except Exception:
+            pass
 
         return True, None