Add special_type to JSON/API responses and hide animate button for transitions

- Pipeline JSON output now includes special_type field for special segments
(Amin, Takbir, Tahmeed, Basmala, etc.) with empty ref_from/ref_to
- Session API forwards special_type to clients
- Animate button hidden for transition segments (no word spans for MFA)
while Basmala/Isti'adha retain it

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

src/api/session_api.py

@@ -171,7 +171,7 @@ def _format_response(audio_id, json_output):
     """Convert pipeline json_output to the documented API response schema."""
     segments = []
     for seg in json_output.get("segments", []):
-        segments.append({
+        entry = {
             "segment": seg["segment"],
             "time_from": seg["time_from"],
             "time_to": seg["time_to"],
@@ -181,7 +181,10 @@ def _format_response(audio_id, json_output):
             "confidence": seg["confidence"],
             "has_missing_words": seg.get("has_missing_words", False),
             "error": seg["error"],
-        })
+        }
+        if seg.get("special_type"):
+            entry["special_type"] = seg["special_type"]
+        segments.append(entry)
     resp = {"audio_id": audio_id, "segments": segments}
     warning = _gpu_fallback_warning()
     if warning:

src/pipeline.py

@@ -482,18 +482,22 @@ def _run_post_vad_pipeline(
             return parts[0], parts[1] if len(parts) > 1 else parts[0]
         return matched_ref, matched_ref
 
+    from src.alignment.special_segments import ALL_SPECIAL_REFS
+
     segments_list = []
     for i, seg in enumerate(segments):
+        is_special = seg.matched_ref in ALL_SPECIAL_REFS
         segment_data = {
             "segment": i + 1,
             "time_from": round(seg.start_time, 3),
             "time_to": round(seg.end_time, 3),
-            "ref_from": parse_ref(seg.matched_ref)[0],
-            "ref_to": parse_ref(seg.matched_ref)[1],
+            "ref_from": "" if is_special else parse_ref(seg.matched_ref)[0],
+            "ref_to": "" if is_special else parse_ref(seg.matched_ref)[1],
             "matched_text": seg.matched_text or "",
             "confidence": round(seg.match_score, 3),
             "has_missing_words": seg.has_missing_words,
             "potentially_undersegmented": seg.potentially_undersegmented,
+            "special_type": seg.matched_ref if is_special else None,
             "error": seg.error
         }
         segments_list.append(segment_data)

src/ui/segments.py

@@ -276,9 +276,12 @@ def render_segment_card(seg: SegmentInfo, idx: int, audio_int16: np.ndarray = No
     audio_html = ""
     if audio_int16 is not None and sample_rate > 0 and segment_dir is not None:
         audio_src = encode_segment_audio(audio_int16, sample_rate, seg.start_time, seg.end_time, segment_dir, idx, inline=audio_inline)
-        # Add animate button only if segment has matched_ref (Quran text with word spans)
+        # Add animate button only if segment has a Quran verse ref (word spans for animation).
+        # Basmala/Isti'adha get animate because they have indexed word spans for MFA.
+        # Transition segments (Amin, Takbir, Tahmeed) don't.
         animate_btn = ""
-        if seg.matched_ref:
+        _ANIMATABLE_SPECIALS = {"Basmala", "Isti'adha", "Isti'adha+Basmala"}
+        if seg.matched_ref and (seg.matched_ref not in ALL_SPECIAL_REFS or seg.matched_ref in _ANIMATABLE_SPECIALS):
             animate_btn = f'<button class="animate-btn" data-segment="{idx}" disabled>Animate</button>'
         audio_html = f'''
         <div class="segment-audio">