Issue: docs(openapi): Show API version selection dropdown in API Reference

Add a version selection dropdown in API reference to allow exploring v2 APIs

Resolution: <think>
PR Context:
- Title: docs(openapi): Show API version selection dropdown in Mintlify
- Merged: 2025-06-13T09:03:06Z
- Files changed: 30 files
- Commits: 7 commits

Implementation approach:
## Type of Change
<!-- Put an `x` in the boxes that apply -->

- [ ] Bugfix
- [ ] New feature
- [ ] Enhancement
- [ ] Refactoring
- [ ] Dependency updates
- [x] Documentation
- [ ] CI/CD

## Description
<!-- Describe your changes in detail -->
- Moved both `v1` and `v2` API docs under `api-reference` directory
- Renamed `openapi_spec.json` files for v1 and v2
- Updated OpenAPI spec file paths in `openapi` crate
- Modified OpenAPI spec path in CI pipeline

### Additional Changes
</think>

To implement this, you'll need to modify:


**Detailed Implementation:**


**Commit 1:** docs(openapi): Show API version selection dropdown in Mintlify (#8333)
Files to modify:


**crates/openapi/src/main.rs**
  Modify existing code