Decouple API contract from internal models by introducing dedicated DTOs for requests and responses.
- Add Response DTOs for all resources (API Keys, Bindings, Models, Namespaces, etc.)
- Update Swagger annotations to use DTOs with field examples instead of internal models
- Refactor handlers to bind and return DTO structures
- Consolidate request/response definitions in the dto package
Add admin endpoints to list and revoke child keys under a master.
Standardize OpenAPI responses to use ResponseEnvelope with MapData
for error payloads, and regenerate swagger specs accordingly.
Add response envelope middleware to standardize JSON responses as
`{code,data,message}` with consistent business codes across endpoints.
Update Swagger annotations and tests to reflect the new response shape.
BREAKING CHANGE: API responses are now wrapped in a response envelope; clients must read payloads from `data` and handle `code`/`message` fields.
