Feat/openapi better impact

[snow-ghost]

Summary

This PR improves OpenAPI / Swagger compatibility in ocli and updates the
README to describe the new user-facing capabilities.

What changed

Better request generation

• Added query and path parameter serialization from OpenAPI / Swagger
  metadata
• Added support for array and object-style query parameters such as
  deepObject, pipeDelimited, and Swagger 2 collection formats
• Added automatic API base URL detection from OAS servers
• Added automatic API base URL detection from Swagger 2 host, basePath,
  and schemes
• Added operation-level and path-level server overrides when the spec defines
  endpoint-specific targets

User impact

These changes improve compatibility with real-world specs, especially APIs
that:

• define payloads outside simple path/query parameters
• rely on inherited path parameters
• use local references
• require header/cookie parameters
• depend on non-trivial parameter serialization
• define their base URL inside the specification instead of requiring manual
  profile setup

Documentation

README was updated to describe the new feature set as user-facing
capabilities instead of internal phase reporting.