feat: Windows stack (daemon, installer, GUI)

Components:
- ostp-daemon: Windows Service with Named Pipe IPC
- ostp-installer: Setup wizard with admin privileges
- ostp-gui: Tauri dark theme UI (450x600)

Features:
- Background service management (OspabGuard)
- IPC commands: CONNECT/DISCONNECT/STATUS
- Firewall rules auto-configuration
- Wintun driver placeholder (download from wintun.net)
- Real-time stats display (upload/download/ping)

Note: Requires wintun.dll download for full functionality

Cargo.toml

@@ -1,6 +1,6 @@
 [workspace]
 resolver = "2"
-members = ["ostp", "oncp", "osn", "osds", "ostp-server", "ostp-client", "ostp-guard", "oncp-master", "ostp-setup"]
+members = ["ostp", "oncp", "osn", "osds", "ostp-server", "ostp-client", "ostp-guard", "oncp-master", "ostp-daemon", "ostp-installer", "ostp-gui"]
 
 [workspace.package]
 version = "0.1.0"