Merge path-level OpenAPI parameters

[kriptoburak]

Summary

• merge path-level parameters into endpoint details, with operation parameters overriding matching in/name pairs
• include path-level parameters in get_types schema collection
• add focused coverage for endpoint output and type generation

Validation

• pnpm fmt
• pnpm lint
• pnpm typecheck
• pnpm test --run
• git diff --check