Add OpenAPIOptions controls to hide routes and suppress default error responses

[moutonjeremy]

Adds two new OpenAPIOptions fields:

• Hidden: skip an operation from the generated spec while still serving traffic
• Errors: []any{} (explicit empty slice): suppress the framework's default 400/422/404/4XX entries

[Copilot]

Pull request overview

This PR adds an explicit opt-out mechanism for framework-generated default error responses in the generated OpenAPI spec, allowing “no error contract” endpoints (e.g., health checks) to document only their success response.

Changes:

• Treat OpenAPIOptions.Errors: []any{} (non-nil, length 0) as a signal to suppress all default error responses in the OpenAPI spec.
• Update OpenAPI generation to honor this opt-out for the legacy 4XX catch-all and default 400/422/404 responses.
• Document the behavior in the README and add regression tests covering nil vs empty vs nil-only Errors slices.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
README.md	Documents the new “explicit empty Errors slice” opt-out behavior and clarifies nil vs empty semantics.
fiberoapi.go	Implements suppression of default OpenAPI error responses when Errors is explicitly empty.
custom_errors_test.go	Adds tests validating suppression behavior and preserving backward compatibility for nil and nil-only slices.

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[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 3 comments.