实现 video batch 自动清理与按需标注视频，并补充子进程调用测试。

batch 完成后仅保留数据库文本结果，勾选时才生成临时标注视频（24h TTL）；新增 FastAPI 到 reference bundle 与 algorithm_runner 的单元测试。

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/tests/test_video_batch_cleanup.py

@@ -0,0 +1,101 @@
+from __future__ import annotations
+
+import time
+from pathlib import Path
+
+from app.services.video_batch_cleanup import (
+    VISUALIZATION_FILENAME,
+    purge_batch_artifacts,
+    purge_expired_visualizations,
+    purge_surgery_batch_tree,
+    purge_visualization_artifacts,
+    stage_visualization_pending,
+    visualization_output_path,
+    visualization_pending_input_path,
+    visualization_pending_result_path,
+)
+
+
+def test_stage_visualization_pending_copies_mp4_and_tsv(tmp_path: Path) -> None:
+    root = tmp_path / "video_batch"
+    source = tmp_path / "source.mp4"
+    tsv = tmp_path / "result.tsv"
+    source.write_bytes(b"mp4-bytes")
+    tsv.write_text("rank\tx\n1\ta\n", encoding="utf-8")
+
+    stage_visualization_pending(root, "100001", source_mp4=source, result_tsv=tsv)
+
+    assert visualization_pending_input_path(root, "100001").read_bytes() == b"mp4-bytes"
+    assert visualization_pending_result_path(root, "100001").read_text(encoding="utf-8") == tsv.read_text(
+        encoding="utf-8"
+    )
+
+
+def test_purge_batch_artifacts_removes_cache_and_uploads(tmp_path: Path) -> None:
+    root = tmp_path / "video_batch"
+    surgery_id = "100001"
+    digest = "d" * 64
+    candidate_key = "c1"
+    cache_entry = root / "cache" / surgery_id / digest / candidate_key
+    (cache_entry / "input").mkdir(parents=True)
+    (cache_entry / "input" / "input.mp4").write_bytes(b"x" * 100)
+    (cache_entry / "output").mkdir(parents=True)
+    (cache_entry / "output" / "result.tsv").write_text("ok\n", encoding="utf-8")
+    (cache_entry / "work").mkdir(parents=True)
+    (cache_entry / "work" / "features").mkdir(parents=True)
+    (cache_entry / "work" / "features" / "input.npy").write_bytes(b"npy")
+    (root / surgery_id / "upload").mkdir(parents=True)
+    (root / surgery_id / "upload" / "upload.mp4").write_bytes(b"upload")
+    (root / surgery_id / "input").mkdir(parents=True)
+    (root / surgery_id / "input" / "abc.mp4").write_bytes(b"input")
+
+    purge_batch_artifacts(root, surgery_id, digest=digest, candidate_key=candidate_key)
+    purge_surgery_batch_tree(root, surgery_id)
+
+    assert not cache_entry.exists()
+    assert not (root / surgery_id).exists()
+
+
+def test_purge_visualization_artifacts_keeps_browser_mp4(tmp_path: Path) -> None:
+    out_dir = tmp_path / "vis" / "100001"
+    out_dir.mkdir(parents=True)
+    browser = out_dir / VISUALIZATION_FILENAME
+    raw = out_dir / "result_vis_source.mp4"
+    part = out_dir / "result_vis.part.mp4"
+    browser.write_bytes(b"browser")
+    raw.write_bytes(b"raw")
+    part.write_bytes(b"part")
+
+    purge_visualization_artifacts(out_dir)
+
+    assert browser.is_file()
+    assert not raw.exists()
+    assert not part.exists()
+
+
+def test_purge_expired_visualizations_removes_old_vis_mp4(tmp_path: Path) -> None:
+    root = tmp_path / "video_batch"
+    vis_path = visualization_output_path(root, "100001")
+    vis_path.parent.mkdir(parents=True)
+    vis_path.write_bytes(b"vis")
+    old = time.time() - (25 * 3600)
+    import os
+
+    os.utime(vis_path, (old, old))
+
+    removed = purge_expired_visualizations(root, ttl_hours=24.0)
+
+    assert removed == 1
+    assert not vis_path.exists()
+
+
+def test_purge_expired_visualizations_keeps_recent_vis_mp4(tmp_path: Path) -> None:
+    root = tmp_path / "video_batch"
+    vis_path = visualization_output_path(root, "100002")
+    vis_path.parent.mkdir(parents=True)
+    vis_path.write_bytes(b"vis")
+
+    removed = purge_expired_visualizations(root, ttl_hours=24.0)
+
+    assert removed == 0
+    assert vis_path.is_file()