feat: add blazor-hello-world template (Blazor WASM .NET 10 + Motoko) - #40

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Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5, actions/create-github-app-token@d72941d797fd3113feb6b93fd0dec494b13a2547, actions/github-script@d7906e4ad0b1822421a7e6a35d5ca353c962f410, actions/setup-python@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/