Environment overrides
TODO list:
- Server/process: PORT, DATA_DIR, CONFIG_FILE, SLOW_QUERY_MS.
- Embeddings: EMBEDDING_PROVIDER, EMBEDDING_MODEL, EMBEDDING_BASE_URL, OPENAI_API_KEY, EMBEDDING_TIMEOUT_SECS.
- Guards: DISK_MIN_FREE_BYTES, DISK_READONLY_ON_LOW_SPACE, CACHE_MAX_BYTES.
- Index/search tuning: INDEX_TYPE, EXECUTION_MODE, PARALLEL_SEARCH, NUM_THREADS, SEARCH_FILTER_OVERFETCH.
- Limits: LIMIT_MAX_VECTORS, LIMIT_MAX_BYTES, LIMIT_MAX_VECTOR_BYTES.
- How precedence works vs. config file defaults.