fix(14-04): correct Segment constructor parameter

Change Segment(index=1, ...) to Segment(id=1, ...) to match
the actual Segment class definition in parser.py.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

kb_workflow/srt/semantic_engine.py

@@ -581,7 +581,7 @@ class UnifiedSegmentationStrategy:
         from kb_workflow.srt.parser import Segment
 
         virtual_segment = Segment(
-            index=1,
+            id=1,
             start_time=0.0,
             end_time=1.0,
             text=chunk_text