[AI] DX: add recommended VS Code extensions for onboarding (#8303)

* [AI] Add recommended VS Code extensions for onboarding

Add a .vscode/extensions.json so contributors are prompted to install the
oxc formatter (matching the configured editor.defaultFormatter), plus the
Playwright and Vitest extensions. Whitelist the file in .gitignore.

Co-Authored-By: Claude Opus 4.8 <[email protected]>
Claude-Session: https://claude.ai/code/session_01G1m2LJehnDTuhbvBhRdCze

* [AI] Add release notes for VS Code recommended extensions

Co-Authored-By: Claude Opus 4.8 <[email protected]>
Claude-Session: https://claude.ai/code/session_01G1m2LJehnDTuhbvBhRdCze

---------

Co-authored-by: Claude <[email protected]>

.gitignore

@@ -59,6 +59,7 @@ bundle.mobile.js.map
 # VSCode
 .vscode/*
 !.vscode/settings.default.json
+!.vscode/extensions.json
 
 # IntelliJ IDEA
 .idea

.vscode/extensions.json

@@ -0,0 +1,7 @@
+{
+  "recommendations": [
+    "oxc.oxc-vscode",
+    "ms-playwright.playwright",
+    "vitest.explorer"
+  ]
+}

upcoming-release-notes/vscode-recommended-extensions.md

@@ -0,0 +1,6 @@
+---
+category: Maintenance
+authors: [MatissJanis]
+---
+
+Add a `.vscode/extensions.json` so contributors are prompted to install the recommended oxc formatter, Playwright, and Vitest extensions.