phase 4

core/detect/checkpoint/__init__.py

@@ -0,0 +1,19 @@
+"""
+Checkpoint system — Timeline + Checkpoint tree.
+
+    detect/checkpoint/
+        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 (
+    create_timeline,
+    get_timeline_frames,
+    get_timeline_frames_b64,
+    save_stage_output,
+    load_stage_output,
+)
+from .frames import save_frames, load_frames
+from .runner_bridge import checkpoint_after_stage, reset_checkpoint_state, get_timeline_id