V5.2.1

Highlights

• bump package version to 5.2.1
• fix xr_cubemx_cfg recovery when the embedded LibXR submodule checkout or metadata is broken
• keep git submodule sync for valid existing checkouts so mirror URL changes such as github <-> gitee still propagate

Recovery coverage

• broken .git/modules/.../HEAD
• dangling checkout symlink
• stale plain directory at the checkout path
• linked git worktree project root