Adds the proxy's OpenAPI spec to the repo as openapi.json so diff tooling has a
committed baseline, and replaces the inline drift check with the update/verify
script pair Kubernetes uses so the same command runs locally and in CI.
- scripts/update-codegen.sh is the single writer for generated artifacts
- scripts/verify-codegen.sh runs it and fails on any git status change
- the sync job now runs on every PR instead of a path filter, so routes defined
outside litellm/proxy (enterprise/**) can no longer land a stale spec
- git status --porcelain replaces git diff, which was blind to untracked files
