feat(desktop): adiciona Raven Service e corrige UAC

- Implementa Windows Service (raven-service) para operacoes privilegiadas
- Comunicacao via Named Pipes sem necessidade de UAC adicional
- Adiciona single-instance para evitar multiplos icones na bandeja
- Corrige todos os warnings do clippy (rustdesk, lib, usb_control, agent)
- Remove fallback de elevacao para evitar UAC desnecessario
- USB Policy e RustDesk provisioning agora usam o servico quando disponivel

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

apps/desktop/src-tauri/Cargo.lock

@@ -80,10 +80,12 @@ dependencies = [
  "tauri-plugin-notification",
  "tauri-plugin-opener",
  "tauri-plugin-process",
+ "tauri-plugin-single-instance",
  "tauri-plugin-store",
  "tauri-plugin-updater",
  "thiserror 1.0.69",
  "tokio",
+ "uuid",
  "winreg",
 ]
 
@@ -4748,6 +4750,21 @@ dependencies = [
  "tauri-plugin",
 ]
 
+[[package]]
+name = "tauri-plugin-single-instance"
+version = "2.3.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dd707f8c86b4e3004e2c141fa24351f1909ba40ce1b8437e30d5ed5277dd3710"
+dependencies = [
+ "serde",
+ "serde_json",
+ "tauri",
+ "thiserror 2.0.17",
+ "tracing",
+ "windows-sys 0.60.2",
+ "zbus",
+]
+
 [[package]]
 name = "tauri-plugin-store"
 version = "2.4.0"