Add codefix support in the TypeSpec playground

[Copilot]

• Export resolveCodeFix from packages/compiler/src/index.ts
• Add updateDiagnosticsForCodeFixes() function and working code action provider in packages/playground/src/services.ts
• Update packages/playground/src/react/playground.tsx to call updateDiagnosticsForCodeFixes() after each compilation
• Split changelog into separate entries for compiler and playground
• Build and lint pass, CodeQL security check clean

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Codefixes in the playground</issue_title>
<issue_description>PR here #2888 add codefixes support but due to how the language server and playground differ in reporting diagnostic we cannot easily make use of the codefixes in the playground.
So separating that implementation</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Codefixes in the playground #2917

---

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[timotheeguerin]

/azp run typespec - pr tools

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[azure-sdk]

You can try these changes here

🛝 Playground	🌐 Website	🛝 VSCode Extension

[timotheeguerin]

Works well

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/microsoft/typespec/@typespec/compiler@9819

npm i https://pkg.pr.new/microsoft/typespec/@typespec/playground@9819

commit: 93422c2

[github-actions]

All changed packages have been documented.

• ✅ @typespec/compiler
• ✅ @typespec/playground

Show changes

@typespec/compiler - feature ✏️

Export resolveCodeFix function to allow resolving a CodeFix into CodeFixEdit[] without the LSP layer.

@typespec/playground - feature ✏️

Add codefix support in the playground. Quick fixes are now surfaced as Monaco code actions when the cursor is on a diagnostic.