- Remove Rev.ai and Gemini STT backends, LLM transcript enrichment, noisy-audio auto-upgrade to Rev.ai, google-genai, and REVAI_ACCESS_TOKEN reads. - Keep exactly three STT backends: parakeet, parakeet-cpp, and confidential. - Treat stale or unknown configured backends as unset with a warning so auto-resolution can select the correct lane; below-floor memory now surfaces the local requirement even when GOOGLE_API_KEY is set. - Run local diarization for parakeet-cpp when overlap meets the threshold. - Keep audio.schema.json byte-identical; reader-side legacy corrected/emotion/topics/setting compatibility remains and no migration is required. BREAKING CHANGE: Rev.ai and Gemini are no longer selectable STT backends, transcript enrichment and noisy-audio cloud upgrade are removed, and STT backend selection no longer falls back to a hardcoded default for stale backend names. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>