[fakayser]

Complete source refresh previously retained an entity's old description even after its source metadata changed. This PR adopts the refreshed entity description, including clearing removed descriptions. Matching descriptions from multiple sources are accepted; conflicting descriptions are rejected. Sources-only refresh and entities without external sources retain their descriptions.

Regression coverage verifies changed, empty and removed descriptions, multiple sources, read-only comparison, repeated refresh, and the ODCS HTTP flow through save and reload.

Release preparation bumps the package and lockfile to 2.1.1 and adds release notes covering this fix and changes already merged since 2.1.0. After merging, create the protected v2.1.1 tag on the merged main commit to run the existing release workflow and publish its tested wheel and source archive to GitHub Releases.

Validation:

• 145 targeted source metadata, mappings, Unity Catalog, builtin integration and navigation tests passed, including unchanged plugin behavior.
• Ruff, pinned ty and documentation validation with Node 24 passed.
• uv build produced the 2.1.1 wheel and source archive.
• Installed-wheel smoke checks passed in a separate environment: CLI, bundled resources, offline ODCS metadata and API readiness/authentication.
• The full solution-dependent suite runs in PR CI using its pinned fixture.