Fix Remotion-first rendering docs and post-render verification gaps

Compose-director had contradictory instructions: Step 2 described Remotion
captions/audio, but Steps 5/5b gave detailed FFmpeg code that agents followed
instead. This caused three failures in production: FFmpeg subtitles instead of
Remotion CaptionOverlay, missing audio (mixed externally but never embedded in
Remotion props), and skipped audio verification in post-render review.

Changes:
- compose-director: Remotion is now DEFAULT for audio, captions, text overlays;
  FFmpeg is labeled FALLBACK only. Post-render review has mandatory ffprobe gate
  and audio transcription with explicit stop conditions.
- remotion.md: routing table updated (captions/audio → Remotion), added universal
  Post-Render Verification Protocol for all pipelines (only 2/10 had one).
- scene-director, asset-director: added pitfall for AI-generated text in CTA
  screens — must use Remotion text_card for verbatim text.
- image-provider-usage: added Recraft V4 caveat (style param causes 422 on fal.ai).
- recraft_image.py: documented the style parameter 422 issue inline.

skills/creative/image-provider-usage.md

@@ -12,7 +12,7 @@
 | `flux_image` | FLUX 2 Pro via fal.ai | ~$0.03-0.05 | ~5-10s | Photorealism, general purpose, workhorse |
 | `grok_image` | Grok Imagine Image (xAI) | $0.02/output + $0.002/input edit image | ~5-15s | Image edits, style transfer, multi-image compositing |
 | `openai_image` | GPT Image 1 (OpenAI) | ~$0.01-0.17 | ~5-15s | Complex instructions, text in images, multi-element |
-| `recraft_image` | Recraft V4 via fal.ai | ~$0.04-0.25 | ~5-10s | Logos, SVG vectors, brand assets, text rendering |
+| `recraft_image` | Recraft V4 via fal.ai | ~$0.04-0.25 | ~5-10s | Logos, SVG vectors, brand assets, text rendering (see caveat below) |
 | `local_diffusion` | Stable Diffusion (local) | Free | ~30s+ | Offline, privacy, free |
 | `image_gen` | Multi (legacy, deprecated) | Varies | Varies | **Deprecated** — use `image_selector` or per-provider tools |
 
@@ -46,6 +46,12 @@
 | **Budget/free project** | `pexels_image` or `pixabay_image` | Free, immediate | `local_diffusion` |
 | **Offline/air-gapped** | `local_diffusion` | No network needed | — |
 
+## Provider-Specific Caveats
+
+### Recraft V4 via fal.ai
+- **`style` parameter causes 422 errors** (as of 2026-04). The `style` enum values (`digital_illustration`, `realistic_image`, etc.) are rejected by fal.ai's Recraft V4 endpoint. **Workaround:** encode style direction in the prompt text instead (e.g. "digital illustration of a tooth cross-section" rather than `style="digital_illustration"`). The `image_size` and `colors` parameters work fine.
+- **Text rendering is unreliable for exact business names.** Recraft (like all AI image models) may hallucinate wrong text. For any scene where text must be verbatim (CTA screens, business names, phone numbers), use Remotion `text_card` instead of generating an image with text.
+
 ## Cost-Quality Tradeoff
 
 ```