test: Phase 7 - Testing & Polish

[CalvinAllen]

Overview

Comprehensive testing, performance optimization, accessibility review, and error handling improvements.

Tasks

Testing

• Unit tests for ManifestService (parsing, serialization)
• Unit tests for ValidationService
• Integration tests for message passing
• E2E testing with real extension manifests
• Test with various extension types (language, theme, debugger, etc.)

Performance

• Profile webview rendering
• Optimize large manifest handling
• Debounce document updates
• Lazy load views

Accessibility

• Keyboard navigation throughout UI
• Screen reader support (ARIA labels)
• Focus management
• High contrast theme support

Error Handling

• Graceful handling of malformed JSON
• Validation error display
• Recovery from sync errors
• User-friendly error messages

Polish

• Loading states
• Empty states
• Tooltips for complex fields
• Field descriptions from schema

Documentation

• Complete README.md with features, screenshots
• CHANGELOG.md following Keep a Changelog format
• Inline code documentation

Test Manifests to Verify

Test with package.json files from:

• Simple command extension
• Language extension with grammar
• Theme extension
• Debugger extension
• Multi-feature extension
• Extension pack
• Web extension

Acceptance Criteria

• All unit tests pass
• E2E tests pass with real manifests
• UI is fully keyboard navigable
• Screen reader can navigate all fields
• Errors display user-friendly messages
• Performance acceptable with large manifests
• README has complete documentation
• CHANGELOG documents all features

Parent Issue

Part of #1