Integrate ElevenLabs Scribe (best multilingual STT 2026)

ElevenLabs Scribe replaces local Whisper as default transcription:
- 96.7% accuracy English, 2.4% WER Indonesian (vs Whisper 7.7%)
- 18x faster (200s song = 11s vs 3-5 min on CPU)
- No hallucinations on songs (Whisper invented 'Pony und Kleid' for 'Bonnie und Clyde')
- 99 languages supported, including SLO/HR/BS/SR
- $0.40/h pricing, ~$0.022 per 200s song

Implementation:
- transcribe_with_elevenlabs() function uses Scribe v1
- ISO 639-1 ↔ 639-3 mapping (Scribe needs 'deu' not 'de')
- Word-level timestamps converted to pseudo-segments (close on 0.6s pause or 6s duration)
- 24MB upload limit guard with auto-fallback to local

Default whisper_provider='auto':
- If ELEVENLABS_API_KEY set → use Scribe
- Otherwise → fallback to local faster-whisper
- 'elevenlabs' strict mode: no fallback
- 'local' strict mode: skip Scribe entirely

Tested on Ben Zucker - Ohne dich: Scribe correctly transcribed
'Wir sind Bonnie und Clyde, zu allem bereit' where local Whisper hallucinated.

app/main.py

@@ -247,6 +247,9 @@ def process_job(job_id):
                 # Brez extension
                 fn_hint = Path(job["filename"]).stem
                 cmd += ["--filename-hint", fn_hint]
+            # STT provider (elevenlabs = Scribe, local = faster-whisper, auto = preferiraj Scribe)
+            if job.get("whisper_provider"):
+                cmd += ["--whisper-provider", job["whisper_provider"]]
             # lang: če None ali 'auto', pusti analyze.py auto-detect
             if job.get("lang") and job["lang"] not in ("auto", ""):
                 cmd += ["--lang", job["lang"]]
@@ -500,6 +503,8 @@ class StartJobIn(BaseModel):
     # LLM za semantično analizo + popravke
     llm_provider: str = "claude"  # claude / gemini / auto
     llm_model: Optional[str] = None  # specifičen model (privzeto najboljši za provider)
+    # STT provider (Scribe je 18x hitreje + boljša multilingual accuracy)
+    whisper_provider: str = "auto"  # auto / elevenlabs / local
 
 
 # ────────────────────────────────────────────────────────────────
@@ -605,6 +610,7 @@ async def start_processing(
         quality=payload.quality,
         llm_provider=payload.llm_provider,
         llm_model=payload.llm_model,
+        whisper_provider=payload.whisper_provider,
         current_step="V vrsti za obdelavo",
         # Počisti pretekle napake (retry-friendly)
         chorus_error=None,