fix: resub response uses seg_start/seg_end to match Segment.CodingKeys

handle_resub was returning 'start'/'end' but Swift Segment expects
'seg_start'/'seg_end' — caused keyNotFound decoding error.

Author: leeyc09

silence_cutter/server.py

@@ -645,8 +645,8 @@ def _parse_time(s):
     out_segments = []
     for seg in raw_segments:
         out_segments.append({
-            "start": seg.seg_start,
-            "end": seg.seg_end,
+            "seg_start": seg.seg_start,
+            "seg_end": seg.seg_end,
             "text": seg.text,
             "words": [
                 {"text": w.text, "start": w.start, "end": w.end}