Add reusable db-sqlite foundation module

[lloydrichards]

Parent

Part of #139.

What to build

Add a reusable SQLite database foundation module for generated applications. This should be independent of chat so future modules can depend on the same database story.

This issue should establish the basic scaffold pattern for SQLite configuration, connection/layer wiring, and migrations.

Helpful context

• Current package/server module patterns: packages/catalog/src/registry/modules/packages.ts, packages/catalog/src/registry/modules/server.ts
• Lucas Postgres repository pattern: .reference/effect-ai-chat-example/packages/server/src/db/

Acceptance criteria

• Add a db-sqlite module or equivalent database foundation module.
• Generated code includes SQLite configuration and connection/layer wiring.
• Generated code includes a migration story suitable for scaffolded apps.
• Include a tiny verification path, such as a health query or demo table.
• The module is independent of chat and can be reused by future persistence modules.
• Add/update scaffold tests for the new module.

Blocked by

None - can start independently, though it will be consumed by chat persistence later.