NW
4b8144ac40
refactor(arch): split database.js into migrations + connection module (#57)
- database.js: 292→42 lines (connection + async helpers only)
- 001_initial_schema.js: 7 CREATE TABLE statements in transaction
- 002_add_columns.js: 5 ALTER TABLE checks with checkColumnExists
- 003_add_indexes.js: 6 CREATE INDEX statements
- runner.js: versioned migration runner with _meta table
- index.js: calls runMigrations() + cleanUpInvalidForeignKeys()
- ALLOWED_TABLES whitelist preserved in runner.js
- Schema version tracked in _meta table for idempotent runs