perf: optimize state management, add HTTPS validation, improve UI performance

- Add HTTPS-only validation for APK downloads and update checks
- Use .select() for Riverpod providers to prevent unnecessary rebuilds
- Add keys to all list builders for efficient updates
- Implement request cancellation for outdated API requests
- Debounce all network requests (URLs and searches)
- Limit file existence cache to 500 entries
- Add ref.onDispose for timer cleanup
- Add error handling for share intent stream
- Redesign About page with Material Expressive 3 style
- Rename Search tab to Home
- Remove Features section from README

README.md

@@ -15,16 +15,6 @@ Get Spotify tracks in true FLAC from Tidal, Qobuz & Amazon Music — no account
 
 ### [Download](https://github.com/zarzet/SpotiFLAC-Mobile/releases)
 
-## Features
-
-- Download tracks, albums, and playlists from Spotify links
-- True lossless FLAC quality from Tidal, Qobuz & Amazon Music
-- Material Expressive 3 design with dynamic colors
-- High performance rendering with Impeller (Vulkan)
-- Concurrent downloads up to 3 simultaneous
-- Real-time download progress tracking
-- Download notifications
-
 ## Screenshots
 
 <p align="center">