test(integration): add integration tests

[Snider]

Finding

Integration tests covering module loading, event dispatch, and cross-module interactions are lacking.

Fix

Add integration tests that verify the full lifecycle: module discovery, event registration, service provider loading, and multi-tenant scoping.

Acceptance Criteria

• Integration test for module discovery and registration lifecycle
• Integration test for event dispatch and listener invocation
• Integration test for multi-tenant query scoping
• Integration test for middleware pipeline
• Tests use Pest syntax
• Tests run against a real (SQLite) database

[Snider]

Parent: #106