Fix TypeScript apphost for CommonJS projects

[sebastienros]

Fixes #16124

• Generate TypeScript AppHosts with an async function main() wrapper instead of top-level await so brownfield CommonJS projects work without changing package module semantics.
• Update generated ESLint config to allow void main() with @typescript-eslint/no-floating-promises.
• Add regression coverage for scaffolded TypeScript AppHosts and aspire init in existing CommonJS and ESM package configurations.

[github-actions]

🚀 Dogfood this PR with:

⚠️ WARNING: Do not do this without first carefully reviewing the code of this PR to satisfy yourself it is safe.

curl -fsSL https://raw.githubusercontent.com/microsoft/aspire/main/eng/scripts/get-aspire-cli-pr.sh | bash -s -- 16538

Or

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iex "& { $(irm https://raw.githubusercontent.com/microsoft/aspire/main/eng/scripts/get-aspire-cli-pr.ps1) } 16538"

[Copilot]

Pull request overview

This PR updates Aspire’s TypeScript AppHost scaffolding/templates to work in CommonJS projects by removing top-level await usage, while also updating linting and adding regression coverage across scaffold/init scenarios.

Changes:

• Generate TypeScript AppHosts with an async function main() wrapper and invoke it via void main(); (instead of top-level await).
• Update generated/template ESLint flat config to allow void with @typescript-eslint/no-floating-promises (ignoreVoid: true).
• Add unit + CLI E2E regression coverage, including an aspire init scenario for a CommonJS repo.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tests/Aspire.Hosting.CodeGeneration.TypeScript.Tests/TypeScriptLanguageSupportTests.cs	Asserts the scaffolded apphost.ts uses main() wrapper and ESLint config includes ignoreVoid.
tests/Aspire.Cli.EndToEnd.Tests/TypeScriptPolyglotTests.cs	Adds E2E verification for aspire init in a CommonJS repo and validates the generated AppHost runs without the TS1309/top-level-await failure.
src/Aspire.Hosting.CodeGeneration.TypeScript/TypeScriptLanguageSupport.cs	Changes scaffolded apphost.ts to avoid top-level await and updates scaffolded ESLint config to allow void usage.
src/Aspire.Cli/Templating/Templates/ts-starter/eslint.config.mjs	Allows void usage for no-floating-promises.
src/Aspire.Cli/Templating/Templates/ts-starter/apphost.ts	Wraps starter AppHost logic in async function main() and invokes it.
src/Aspire.Cli/Templating/Templates/py-starter/eslint.config.mjs	Allows void usage for no-floating-promises.
src/Aspire.Cli/Templating/Templates/py-starter/apphost.ts	Wraps starter AppHost logic in async function main() and invokes it.