CLAUDE: fopen_pose_compare.py — handle timestamp-named COLMAP images

parse_images_txt() now accepts both frame_NNN names and timestamp names
(e.g. 1763232419_474661.png). Introduces sort_key (float) so entries
sort correctly regardless of naming style. fno stays -1 for timestamp
images since no integer frame number is present.
Co-authored-by: Claude <claude@elphel.com>

scripts/fopen_pose_compare.py

@@ -190,14 +190,21 @@ def parse_images_txt(path):
             i += 2
             continue
         m    = re.search(r'frame_(\d+)', name)
-        fno  = int(m.group(1)) if m else -1
+        if m:
+            fno = int(m.group(1))
+            sort_key = float(fno)
+        else:
+            # Timestamp-named images: "1763232419_474661.png" → 1763232419.474661
+            mt = re.match(r'(\d+)_(\d+)\.png', name)
+            sort_key = float(mt.group(1) + '.' + mt.group(2)) if mt else 0.0
+            fno = -1
         R_cw = quat_to_R(qw, qx, qy, qz)
-        entries.append({'frame': fno, 'name': name,
+        entries.append({'frame': fno, 'name': name, 'sort_key': sort_key,
                         'center': colmap_center(R_cw, tx, ty, tz),
                         'R_cw': R_cw,
                         'qw': qw, 'qx': qx, 'qy': qy, 'qz': qz})
         i += 2  # skip POINTS2D line
-    entries.sort(key=lambda e: e['frame'])
+    entries.sort(key=lambda e: e['sort_key'])
     return entries