Batch PostgreSQL constraint introspection

[joe-thom]

Summary

PostgreSQL introspection can now preload primary and unique constraints once per schema. This bounds query volume for databases with many tables.

Why

The existing path runs constraint queries for each table. Large schemas can exceed the database-diff timeout before publishing starts.

What changed

• Adds an optional fourth argument to introspectPgDB.
• Preloads primary and unique constraints once for each selected schema.
• Keeps batching disabled unless the caller opts in.
• Calls the error callback and uses existing per-table queries if a preload fails.

Validation

• The batching tests prove opt-in behavior, snapshot equivalence, query reduction, and fallback after preload errors.
• The package typecheck and repository format check pass.

Stack

Merge bottom to top:

1. Fix PostgreSQL migration dependency order #31 PostgreSQL migration dependency order
2. Handle PostgreSQL JSON expression defaults #33 JSON and JSONB expression defaults
3. Batch PostgreSQL constraint introspection #34 batched constraint introspection (this PR)
4. Prepare drizzle-kit 0.32.4 release #35 0.32.4 release

Rollout and rollback

The new argument is optional and batching defaults to off. This layer does not publish a package or change a consumer.

~ written by Zerg 👾 (wp-e307c37c)