Merge 2025-07-15 batch into the xlsx; tools to detect & re-track

- merge_2025_07_15_into_xlsx.py: pivot the legacy 2025_07_15_metadata_fixed.csv
  into the unified xlsx schema (one row per fly, training_date_time +
  testing_date_time). Backs up the xlsx before writing. 24 new rows
  across machines 076 / 139 / 145 / 268.
- pick_targets.py: --video flag to bypass the inventory's in_xlsx filter,
  so a specific mp4 can be picked outside the normal flow.
- explore_barrier_signal.py: visualises raw y(t), per-frame inter-fly
  distance, and sliding min/mean distance against a known
  barrier-opening time. Used for prototyping the detector.
- detect_barrier_opening.py: per-ROI sliding-window mean-distance
  change-point estimator (median across ROIs). Currently noisy on a
  one-video calibration set; will be re-tuned once the 4 missing
  2025-07-15 videos are re-tracked.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

scripts/pick_targets.py

@@ -363,6 +363,12 @@ def main() -> None:
         "--limit", type=int, default=None,
         help="only process the first N videos",
     )
+    parser.add_argument(
+        "--video", action="append", default=[],
+        metavar="MP4_PATH",
+        help="explicit mp4 path to pick targets for (bypasses the inventory's "
+             "in_xlsx filter). Repeat to specify multiple videos.",
+    )
     args = parser.parse_args()
 
     if not INVENTORY_CSV.exists():
@@ -372,7 +378,27 @@ def main() -> None:
         )
 
     inv = pd.read_csv(INVENTORY_CSV)
-    todo = inv[inv["in_xlsx"] & ~inv["already_tracked"]].copy()
+    if args.video:
+        # Reason: explicit --video paths skip the in_xlsx filter so we can
+        # re-track recordings that aren't in the merged xlsx (e.g. the
+        # 2025-07-15 multi-recording sessions). Each path must exist in
+        # the inventory so we still get machine_name / session_datetime
+        # for the prompt; build a small synthetic todo from those rows.
+        wanted = {str(Path(p).resolve()) for p in args.video}
+        inv["_resolved"] = inv["mp4_path"].apply(lambda p: str(Path(p).resolve()))
+        todo = inv[inv["_resolved"].isin(wanted)].drop(columns="_resolved").copy()
+        missing = wanted - set(
+            inv["mp4_path"].apply(lambda p: str(Path(p).resolve()))
+        )
+        if missing:
+            print(f"⚠ {len(missing)} requested video(s) not in inventory; "
+                  "rebuild it with build_video_inventory.py if needed:")
+            for m in sorted(missing):
+                print(f"    {m}")
+        if todo.empty:
+            sys.exit("No matching videos in inventory.")
+    else:
+        todo = inv[inv["in_xlsx"] & ~inv["already_tracked"]].copy()
     todo = todo.sort_values(
         ["session_date", "machine_name", "session_time"]
     ).reset_index(drop=True)