docs: cleanup README and improve agent guides

[Chesars]

Title

docs: cleanup README and improve AI agent guides

Relevant issues

N/A (documentation improvements)

Pre-Submission checklist

• I have Added testing in the tests/litellm/ directory - N/A (documentation-only changes)
• I have added a screenshot of my new test passing locally - N/A
• My PR passes all unit tests on make test-unit - Will verify
• My PR's scope is as isolated as possible, it only solves 1 specific problem

Type

📖 Documentation

Summary

README.md

• Removed obsolete warnings: Deleted outdated version requirement notices for openai>=1.0.0 and pydantic>=2.0.0 (project is now on v1.80.5)
• Added Responses API note: Included brief mention of litellm.responses() API with link to full documentation

Agent Guides (CLAUDE.md, GEMINI.md, AGENTS.md)

• Added GitHub Templates section: Documented issue and PR templates to guide AI agents when contributing
  • Bug report template (.github/ISSUE_TEMPLATE/bug_report.yml)
  • Feature request template (.github/ISSUE_TEMPLATE/feature_request.yml)
  • Pull request template (.github/pull_request_template.md)

Cleanup

• Removed test_pydantic_fields.py: Deleted temporary debugging script that wasn't referenced anywhere

[vercel]

@Chesars is attempting to deploy a commit to the CLERKIEAI Team on Vercel.

A member of the Team first needs to authorize it.