Use PGlite by default for type generation

[vik319]

Fixes #2.

Running db:generate now uses the existing in-memory PGlite implementation by default, so type and SQL generation no longer requires a running PostgreSQL server. Both the API and CLI use this default; --no-pglite retains the external database option. The CLI awaits generation, and configuration imports use a file URL so the built Node CLI can run on Windows.

The regression test covers both the default and explicit PGlite modes and checks that the generated schema contains the migrated table type. The README documents the default and opt-out.

Validation on Windows with Bun 1.4.2:

• Default-mode regression failed before the fix with an unreachable external database URL and passed after it.
• Full suite: 4 tests, 12 assertions passed.
• tsup build and declaration generation passed.
• Built CLI and bun run db:generate in a separate migration fixture succeeded with DATABASE_URL pointing to localhost port 1; generated SQL and TypeScript were inspected.
• git diff --check passed.

The existing baseline also prints Windows path warnings during tests. Linux/macOS and the external PostgreSQL opt-out were not tested.