feat: Hiddify Yumash Edition - Windows-only fork

Major rewrite focused on Windows and Russian users.

## Added
- Dual-core: sing-box 1.12 + Xray-core for xhttp transport
- TLS Tricks: Mixed SNI Case for DPI bypass
- Russian domains/IPs bypass (geosite-ru, geoip-ru)
- Custom rule-set URLs support
- Ad blocking with customizable filters
- WireGuard LAN server (share VPN to phone)
- Portable mode (settings in portable_data/)
- Fixed window size 900x700
- Donation wallets: BTC, USDT TRC20, TON
- Debug output to console and portable_data/debug/

## Removed
- iOS, Android, Linux, macOS platforms
- IPv6, WARP, Clash API
- Extension system, auto-update
- 18 languages (kept EN, RU only)
- Mobile-specific code

## Updated
- sing-box 1.11 → 1.12.14
- Riverpod 2.x → 3.x
- Flutter SDK 3.19 → 3.24+
- All Flutter packages to latest versions

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: Yumash