Fix speaker diarization: WAV conversion, pyannote 4.0 compat, telemetry bug

- Convert non-WAV audio to 16kHz mono WAV before diarization (pyannote
  v4.0.4 AudioDecoder returns None duration for FLAC, causing crash)
- Handle pyannote 4.0 DiarizeOutput return type (unwrap .speaker_diarization)
- Disable pyannote telemetry (np.isfinite(None) bug with max_speakers)
- Use huggingface_hub.login() to persist token for all sub-downloads
- Pre-download sub-models (segmentation-3.0, speaker-diarization-community-1)
- Add third required model license link in settings UI
- Improve SpeakerManager hints based on settings state
- Add word-wrap to transcript text

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

python/voice_to_notes/services/pipeline.py

@@ -127,15 +127,17 @@ class PipelineService:
                 hf_token=hf_token,
             )
         except Exception as e:
+            import traceback
             print(
                 f"[sidecar] Diarization failed, falling back to transcription-only: {e}",
                 file=sys.stderr,
                 flush=True,
             )
+            traceback.print_exc(file=sys.stderr)
             write_message(
                 progress_message(
                     request_id, 80, "pipeline",
-                    "Diarization unavailable, using transcription only..."
+                    f"Diarization failed ({e}), using transcription only..."
                 )
             )