feat(api): use Tencent 16k_zh_large ASR and remove local Whisper

Standardize ASR on Tencent's dialect-capable engine across all environments,
drop faster-whisper from dependencies and deployment images, and add an
expo-sqlite iOS vendor sync plus pod install in prebuild to prevent native
build failures after npm install.

Co-authored-by: Cursor <cursoragent@cursor.com>

api/docker-compose.yml

@@ -71,7 +71,6 @@ services:
     env_file:
       - .env
     environment:
-      - ASR_MODEL_CACHE_DIR=/app/models/whisper
       - APP_ENV=${APP_ENV:-production}
       - REDIS_URL=redis://redis:6379/0
       - CELERY_REDIS_URL=redis://redis:6379/1