refactor: 升级依赖版本并优化构建系统

- 升级核心依赖 (axum 0.8, tower-http 0.6, alsa 0.11 等)
- 简化交叉编译配置，切换至 Debian 11 提高兼容性
- 新增 Debian 包打包支持 (debuerreotype 模板)
- 移除独立的 mjpeg 解码器，简化视频模块
- 静态链接 libx264/libx265/libopus 到二进制

src/rustdesk/config.rs

@@ -161,8 +161,8 @@ impl RustDeskConfig {
 /// Generate a random 9-digit device ID
 pub fn generate_device_id() -> String {
     use rand::Rng;
-    let mut rng = rand::thread_rng();
-    let id: u32 = rng.gen_range(100_000_000..999_999_999);
+    let mut rng = rand::rng();
+    let id: u32 = rng.random_range(100_000_000..999_999_999);
     id.to_string()
 }
 
@@ -170,10 +170,10 @@ pub fn generate_device_id() -> String {
 pub fn generate_random_password() -> String {
     use rand::Rng;
     const CHARSET: &[u8] = b"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
-    let mut rng = rand::thread_rng();
+    let mut rng = rand::rng();
     (0..8)
         .map(|_| {
-            let idx = rng.gen_range(0..CHARSET.len());
+            let idx = rng.random_range(0..CHARSET.len());
             CHARSET[idx] as char
         })
         .collect()
@@ -226,6 +226,7 @@ mod tests {
 
         // No rendezvous server, relay is None
         config.rendezvous_server = String::new();
+        config.relay_server = None;
         assert_eq!(config.relay_addr(), None);
     }