**Problem**
AI_MODEL_PREFERENCES, JSON env var is not supported +
IS_CONFIG_VARIABLES_IN_DB_ENABLED=false in twenty cloud server
-> No option to set AI_MODEL_PREFERENCES
**Solution**
AI_MODEL_PREFERENCES supports three override sources beyond the
hardcoded code defaults, in priority order:
- DB (IS_CONFIG_VARIABLES_IN_DB_ENABLED=true), the only writable source;
admin-panel mutations persist here
- ENV not usable in Twenty Cloud, which does not handle JSON-format env
vars
- **Introduced in this PR** --> File
(AI_MODEL_PREFERENCES_STORAGE_PATH), a read-only startup fallback, the
only viable override in Cloud/self-managed deployments where DB config
is disabled and JSON env vars are unsupported.
