docs: change Claude badge to Powered instead of Agent SDK

Update README for v0.0.6 and refresh app icon

- Update header tagline to match main repo
- Add v0.0.6 features: multi-engine, skills marketplace, subagents, browser agent, diff stats
- Remove shipped items from vision section (provider-agnostic models)
- Replace icon with current app icon

Update README for v0.0.6 and refresh app icon

- Update header tagline to match main repo
- Add v0.0.6 features: multi-engine, skills marketplace, subagents, browser agent, diff stats
- Remove shipped items from vision section (provider-agnostic models)
- Replace icon with current app icon

Update README for v0.0.6 and refresh app icon

- Update header tagline to match main repo
- Add v0.0.6 features: multi-engine, skills marketplace, subagents, browser agent, diff stats
- Remove shipped items from vision section (provider-agnostic models)
- Replace icon with current app icon

Add light mode screenshot, match GitHub theme preference

Update to macOS Apple Silicon only, add coming soon for other platforms

Update to macOS Apple Silicon only, add coming soon for other platforms

Update to macOS Apple Silicon only, add coming soon for other platforms