[3.6] Add VS Code workspace settings

[vbonk]

What needs to be done

Create .vscode/extensions.json (recommended extensions, language-specific commented) and .vscode/settings.json (formatOnSave, trim whitespace).

Acceptance Criteria

• .vscode/ directory with 2 files
• Matches .editorconfig settings
• init-template uncomments language extension

[vbonk]

Completed in Phase 3 PR #85.