phase 3

detect/checkpoint/__init__.py

@@ -5,6 +5,7 @@ Checkpoint system — Timeline + Checkpoint tree.
         frames.py      — frame image S3 upload/download
         storage.py     — Timeline + Checkpoint (Postgres + MinIO)
         replay.py      — replay (TODO: migrate to new model)
+        runner_bridge.py — checkpoint hook for PipelineRunner
 """
 
 from .storage import (
@@ -15,3 +16,4 @@ from .storage import (
     load_stage_output,
 )
 from .frames import save_frames, load_frames
+from .runner_bridge import checkpoint_after_stage, reset_checkpoint_state