Merge Release 2.1 back into main

[jbrinkman]

Summary
Merge the release/2.1 branch back into main to ensure all release changes and tags are reflected in the primary development branch.

Rationale
Keeping main up to date with the release branch ensures that hotfixes, version bumps, and changelog updates are preserved in ongoing development.

Proposed Steps

• Confirm the latest release branch name (release/2.1 or similar) and upstream tag (e.g., v2.1.0)
• Sync local branches and fetch latest tags
• Create a merge PR from release/2.1 -> main
• Resolve any conflicts (prefer changes from release branch for versioning and changelog)
• Ensure CI passes on the PR
• Merge with a merge commit (not squash) to preserve history
• Delete the release branch if appropriate (after merge)

Validation

• CHANGELOG.md includes 2.1 entries on main
• Version numbers across language packages reflect 2.1
• Tags and release notes remain intact

Notes
If conflicts arise in language-specific modules (Go/Node/Python/Java), coordinate maintainers for sign-off.

/cc @jbrinkman