docs: Rewrite TODO and Notes tutorials with working code and fix documentation issues

- Complete rewrite of TODO tutorial with detailed explanations and verified working code
- Complete rewrite of Notes tutorial demonstrating file dialogs and desktop patterns
- Add screenshots for both tutorials
- Update tutorial overview with improved descriptions
- Fix HTML entity encoding for < character in lifecycle and bridge docs
- Update API status from Beta to Alpha in reference documentation
- Change Beta APIs to Unstable APIs for clarity
- Remove "From Tauri" migration link from navigation
- Update wails.app references to wails.io
- Fix various typos and improve code examples throughout

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Co-Authored-By: Claude <noreply@anthropic.com>