Make initialized type generation work without external Postgres

[gilmarGNJ]

Closes #2.

@algora-pbc /claim #2

pgstrap generate and the API now use an in-memory PGlite database by default, so the existing script produced by pgstrap init needs no external Postgres. --no-pglite / pglite: false retain the external-database path.

The embedded path binds only to loopback, closes its gateway and PGlite instance, and restores both DATABASE_URL and POSTGRES_URI on success or failure. The latter matters because pg-schema-dump gives POSTGRES_URI precedence.

Testing the actual installed package uncovered two additional blockers in this exact workflow, addressed here with regressions:

• Node on Windows requires a file URL when importing the project configuration; the test also includes spaces and # in its directory name.
• A fresh installation resolves the unrestricted node-pg-migrate peer to v9, which exports a named runner. The loader now accepts that as well as the existing v6 default-export forms, without changing dependency versions.

Validation performed locally:

• bun test: 14 passed, 0 failed, including real migrations, CLI/API defaults, the scaffolded script, the compiled Node CLI, export compatibility, error cleanup and environment restoration.
• Build (CJS and DTS), bun run format:check, and git diff --check pass.
• Built and packed the package locally (not published), installed it in a separate initialized fixture, and ran its unchanged bun run db:generate with external database URIs pointing at unused loopback port 1. It exits 0 and generates both typed Zapatos declarations and SQL for a migrated table with defaults and indexes. A repeat run produces the same type-file hash.
• The installed-package check uses Node 22.17.1, Bun 1.4.0, node-pg-migrate 9.0.0 and PGlite 0.3.16; the source suite also exercises the repository-locked node-pg-migrate 6.2.2. Explicit --no-pglite fails with ECONNREFUSED at that unused port, as expected.

AI-assisted implementation and review, with the commands and results above actually run. No claim of human review or bounty award; this is submitted for maintainer evaluation.