feat(ui): upgrade Ant Design and dark theme

[kklldog]

Summary

• Upgrade the admin UI to Ant Design 6, Pro Components 3, Umi Max 4, React 18.3, and TypeScript 5.9.
• Replace legacy dark-mode overrides with the official token-based theme algorithm.
• Migrate route/layout, modal, dropdown, table, and notification APIs for the new stack.
• Bump the server package, assembly, and file version to 1.13.1.
• Prevent stale UI entry HTML from being served after a deployment.

Validation

• npm run tsc
• npm run build
• dotnet build src/AgileConfig.Server.Apisite/AgileConfig.Server.Apisite.csproj --no-restore
• Browser verification of light/dark configuration pages, dashboard, and create-config modal