feat(apigateway): an api-gateway handler owns its own wire response

[uladkasach]

feat(apigateway): an api-gateway handler owns its own wire response

forApiGateway handlers now return an ApiGatewayResponse — any status, any
headers, any body, or none — and the sdk passes it to the wire as written.

the root cause was the wrong type at the output point: invoke returned a
body, so the wire encode had to invent the rest and invented
{ statusCode: 200, body: JSON.stringify(x) }. a body cannot carry a status,
so 204, 308, and xml were inexpressible by construction.

• widen the one contract rather than add a peer export — PickAny<{ status, headers, body }>, so {} is a compile error rather than middys silent 500
• schema is required, z.any() is the explicit opt-out — validation and
  introspection stay on one code path
• asApiGatewayResponseSchema({ body }) lifts a body schema into the envelope
• add genContentTypeCoherenceMiddleware — a body-less response reaches the
  wire with no content-type, which is the twilio 11200 shape retired
• add HttpStatusCode.PERMANENT_REDIRECT_308
• fix: corsInputToCorsConfig handed the vendor origins: undefined, which
  clobbered its [] default and threw from after — every success response of
  a cors: { origins: "*" } handler was a 500
• 15 wire acceptance cases over real http, both payload versions, whole-response
  denylist snapshots

BREAKING CHANGE: invoke returns ApiGatewayResponse rather than a body.
({ x }) becomes ({ body: { x } }). an aws-native { statusCode, body }
return answers 500 with a named error rather than a silent mis-encode.

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🐢🌊 surfed in by seaturtle[bot]

[rhelease]

🐢 released at https://github.com/ehmpathy/sdk-aws-lambda/releases/tag/v0.4.0