Enhance warning display for endpoints with mixed content types

[kioku]

Summary

Endpoints that support JSON alongside unsupported content types currently show warnings only in verbose mode or as a secondary section. These warnings should be more prominent to ensure users understand the limitations.

Current Behavior

When an endpoint supports both application/json and unsupported content types (e.g., multipart/form-data), the warning appears in a separate "Endpoints with partial content type support" section that is easy to miss.

Expected Behavior

Mixed content type warnings should be as prominent as skipped endpoint warnings, clearly indicating that while the endpoint is available, only JSON requests will work.

Example

Current output:

Warning: Skipping 1 endpoints with unsupported content types:
  - POST /upload (multipart/form-data) - endpoint has no supported content types

Endpoints with partial content type support:
  - POST /mixed supports JSON but not: multipart/form-data, application/xml

Proposed output:

Warning: 1 endpoint skipped, 1 endpoint with partial support:

Skipped endpoints (not available):
  - POST /upload (multipart/form-data) - endpoint has no supported content types

Partially supported endpoints (JSON only):
  - POST /mixed accepts: application/json
              ignores: multipart/form-data, application/xml

Context

This issue was identified during PR #12 review. Users need clear visibility into which content types are actually supported for each endpoint.

Related

• PR feat: add --strict flag for partial spec acceptance with warnings #12: feat: add --strict flag for partial spec acceptance with warnings
• Issue feat: Support partial OpenAPI spec acceptance with warnings for unsupported content types #11: Original feature request