Module connection 

SQLite connection setup with PRAGMAs and 0600 permissions.

Opens (or creates) the database file, loads the sqlite-vec extension, applies WAL/journal PRAGMAs, and enforces 0600 file permissions on Unix.

Functions

ensure_schema

open_ro

open_rw

register_vec_extension

Register sqlite-vec GLOBALLY before any connection is opened. Must be called once at program start.