CLAUDE: fopen_pose_compare.py — use timestamp as frame identity, drop scene_idx

Timestamps are unambiguous when using sub-sequences (e.g. 378 of 498
frames).  0-based sequential scene_idx was misleading.

- console top-N table: Scene column replaced with Timestamp
- CSV: scene_idx column removed, timestamp is the identity column
- parse_interframe_xml: drop scene_idx from returned dicts
Co-authored-by: Claude <claude@elphel.com>

scripts/fopen_pose_compare.py

@@ -193,8 +193,7 @@ def parse_interframe_xml(path, skip_rows=None):
     Returns list of dicts sorted by timestamp — same order as COLMAP frame_NNNN
     (elphel_to_colmap.py assigns frame numbers by sorting timestamps).
 
-      scene_idx  — 0-based sequential index
-      timestamp  — float seconds
+      timestamp  — float seconds (from key "1763233715_106222" → 1763233715.106222)
       x/y/z      — position (m) relative to reference scene
       az/tilt/roll — orientation (rad)
     """
@@ -229,7 +228,6 @@ def parse_interframe_xml(path, skip_rows=None):
             continue
         x, y, z, az, tilt, roll = vals
         rows.append({
-            'scene_idx': i,
             'timestamp': ts,
             'x': x,   'y': y,   'z': z,
             'az': az, 'tilt': tilt, 'roll': roll,
@@ -423,10 +421,10 @@ def print_top_pos_residuals(pairs, residuals, s, n=10):
     """Top-n worst position residuals."""
     idx = np.argsort(residuals)[::-1]
     print(f"\n  Top-{n} worst position frames  (1 COLMAP = {1/s:.1f} m):")
-    print(f"  {'Frame':>6}  {'Scene':>6}  {'res(COLMAP)':>12}  {'res(m)':>10}")
+    print(f"  {'Frame':>6}  {'Timestamp':>20}  {'res(COLMAP)':>12}  {'res(m)':>10}")
     for i in idx[:n]:
         c, e = pairs[i]
-        print(f"  {c['frame']:>6}  {e['scene_idx']:>6}  {residuals[i]:>12.4f}  "
+        print(f"  {c['frame']:>6}  {e['timestamp']:>20.3f}  {residuals[i]:>12.4f}  "
               f"{residuals[i]/s:>10.2f}")
 
 
@@ -481,7 +479,7 @@ def main():
     # ── CSV ────────────────────────────────────────────────────────────────
     if args.out:
         base_fields = [
-            'frame', 'scene_idx', 'timestamp',
+            'frame', 'timestamp',
             'colmap_X', 'colmap_Y', 'colmap_Z',
             'xml_x', 'xml_y', 'xml_z',
             'xml_az_rad', 'xml_tilt_rad', 'xml_roll_rad',
@@ -506,7 +504,6 @@ def main():
             for i, (ce, er) in enumerate(pairs):
                 row = {
                     'frame':      ce['frame'],
-                    'scene_idx':  er['scene_idx'],
                     'timestamp':  er['timestamp'],
                     'colmap_X':   ce['center'][0],
                     'colmap_Y':   ce['center'][1],