V5.2.0

Changes

• Fix xr_cubemx_cfg LibXR submodule checkout policy.
• Keep explicit --commit as the only unconditional checkout override.
• Preserve existing/manual LibXR checkouts by default and only upgrade clean older project gitlinks to the package default.
• Bump package version to 5.2.0.

Validation

• PR #12 merged after push CI passed.
• Release workflow will build and publish packages.