fix(routes): fail closed when a response does not match its schema #429

Why

Response schemas are how the API keeps responses minimal. When a response fails its own schema, defineRoute logs the mismatch and sends the raw payload anyway (src/lib/defineRoute.ts, around lines 351 to 362). Any controller that returns more than it should then leaks it, which is the case the validation exists to catch.

What

• On a response schema mismatch, send a generic 500 (InternalErrorSchema) instead of the raw payload, and log the route and the failing paths
• A test that a mismatching response is not sent
• Generated contract tests still pass, so no current route trips this

Done when

No response that fails its schema reaches a client.