build: promote compatible CountryService dependency updates

[natthapolvanasrivilai]

Outcome

Promotes the already-reviewed compatible CountryService dependency slice from develop into main as one clean current-state commit.

Integrity

• Source develop: 7f91bf4da7b057866fbb1b922b6c294f84378623
• This branch tree SHA exactly equals current develop: da9e44ce9908fa3e5759d097a6667a8b2dd009db.
• Diff from current main is limited to the test project and its regenerated lockfile.
• Single-parent commit on current main; no divergent historical graph is imported.

Validation

• Source PR build: update compatible CountryService dependencies #44 aggregate validation: green (29688702787).
• Exact develop push validation: green (29688826753).
• Locked restore passed; Release build 0 warnings/errors; 263/263 tests passed.
• Format, dependency audit, current-tree secret scan, local image build/metadata, and high-severity image scan passed.

Compatibility boundary

The EF Core/Microsoft.Extensions 10.0.10 portion of Dependabot #40 remains excluded because it conflicts with pinned ServiceDefaults EF Core 10.0.5. No mixed assembly graph is introduced.

No deployment, image publication, GitOps/environment write, or database operation.