fix: Support bru-lang format and fix OpenAPI spec compliance

[GyeongHoKim]

Changes

This PR includes fixes for bru-lang format support and OpenAPI 3.0 spec compliance.

Key Changes

1. bru-lang Format Support

   • Added support for parsing .bru files in bru-lang format
   • Resolves the 'missing method or URL' warning reported in issue Skipping item 'register' - missing method or URL #2

2. OpenAPI 3.0 Spec Compliance

   • Changed response codes to string format ('200', '400', etc.) as required by OpenAPI spec
   • Unified version field to string format
   • Cleaned up description format
   • Added requestBody for form-urlencoded and multipart/form-data requests

3. Documentation Improvements

   • Fixed README.md examples (result.openapi → result.spec)
   • Added Sync function usage examples
   • Fixed function name typo (convertBrunoCollectionToAPISync → convertBrunoCollectionToOpenAPISync)

4. Test Files Update

   • Updated all fixture expected-openapi.yml files to correct OpenAPI format

Testing

• All existing tests pass
• OpenAPI spec validation passes

Resolves #2

[gitguardian]

⚠️ GitGuardian has uncovered 1 secret following the scan of your pull request.

Please consider investigating the findings and remediating the incidents. Failure to do so may lead to compromising the associated services or software components.

🔎 Detected hardcoded secret in your pull request

GitGuardian id	GitGuardian status	Secret	Commit	Filename
24268479	Triggered	Username Password	a320c05	tests/fixtures/auth-test-collection/request-with-basic-auth.bru	View secret

🛠 Guidelines to remediate hardcoded secrets

1. Understand the implications of revoking this secret by investigating where it is used in your code.
2. Replace and store your secret safely. Learn here the best practices.
3. Revoke and rotate this secret.
4. If possible, rewrite git history. Rewriting git history is not a trivial act. You might completely break other contributing developers' workflow and you risk accidentally deleting legitimate data.

To avoid such incidents in the future consider

• following these best practices for managing and storing secrets including API keys and other credentials
• install secret detection on pre-commit to catch secret before it leaves your machine and ease remediation.

---

^{🦉 GitGuardian detects secrets in your source code to help developers and security teams secure the modern development process. You are seeing this because you or someone else with access to this repository has authorized GitGuardian to scan your pull request.}