feat(create-app): add community templates registry and selection flow

[derrick-nuby]

Summary

This PR adds community template support to @dhis2/create-app.
Users can now select configured community templates in interactive mode and use them with --template in non-interactive mode.

What Changed

1. Added a community template registry file at packages/create-app/src/community-templates.yaml.
2. Added registry parsing and validation in packages/create-app/src/utils/getCommunityTemplates.js.
3. Added source classification in packages/create-app/src/utils/resolveTemplateSourceInput.js.
4. Updated create flow:
   • interactive Community templates option
   • --template <community-source> support
   • direct Git template fallback for non-listed sources
5. Kept built-in template resolution in index.js and external Git resolution in resolveExternalTemplateSource.
6. Added tests for registry parsing and source resolution.
7. Updated docs/commands/create-app.md.

Initial Community Templates

1. Tailwind + React Router (derrick-nuby/dhis2-ts-tailwind-react-router) with source as unique identifier.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud