Bump @vscode/test-electron to v3.1.0

[Copilot]

Updates @vscode/test-electron from ^2.3.8 to ^3.1.0.

Changes

• package.json: version constraint updated to ^3.1.0
• package-lock.json: resolved to 3.1.0

[rzhao271]

@copilot Avoid skipLibCheck. Upgrade TypeScript to ~5.9, use types/node 22 if not already, and fix any compile errors.

[Copilot]

@copilot Avoid skipLibCheck. Upgrade TypeScript to ~5.9, use types/node 22 if not already, and fix any compile errors.

Done in commit 7f4c4fc (short hash may vary). TypeScript upgraded to ~5.9 (resolves to 5.9.3), @types/node is already ^22.19.1, and no skipLibCheck is used. The build passes cleanly.