The model select fields used provider-specific names (AI_MODEL_TAGS_OLLAMA,
AI_MODEL_TAGS_OPENAI, etc.) but handleSaveAI read from non-existent
formData keys (AI_MODEL_TAGS, AI_MODEL_EMBEDDING). This caused model
values to be silently dropped on save, making the provider appear to
revert. Now reads from the correct provider-specific field names.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>