Investigate and clarify ESM module settings trailing comma issue

[Copilot]

PR Checklist:

• Provide a meaningful description to this PR or mention which issues this fixes.
• Ensure the project builds with npm run build
• Add tests for your change. This includes negative tests (i.e. inputs that need to fail) as well as baseline tests (i.e. how should the directory structure look like?).
• Run the test suite with npm test
• If there are baseline changes, review them and make a separate commit for them with the comment "accept baselines" if they are desired changes
• If you added a required option, also add it to the template creation (.github/create_templates.ts)
• Add a detailed migration description to docs/updates explaining what the user needs to do when manually updating an existing project
• Add your changes to CHANGELOG.md (referencing the migration description and this PR or the issue you fixed)

Description:

Addresses review comment from #1255 regarding a reported missing trailing comma in the ESM module settings block at templates/tsconfig.json.ts:49.

Investigation Results:

Line 49 contains "noEmit": true, with a trailing comma present. Tested JSON generation across multiple scenarios:

• TypeScript with/without ESM
• TypeScript without build with/without ESM
• JavaScript with type checking and ESM

All scenarios generate valid JSON. The template string interpolation correctly preserves commas:

"noEmit": true,
${
  useESM
    ? `
    // ESM module settings
    "module": "ES2022",
    "moduleResolution": "bundler",
`
    : ""
}

    // check JS files...
    "allowJs": true,

Awaiting clarification on specific case that produces invalid JSON.

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