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

build/debian/prerm.tpl

@@ -0,0 +1,28 @@
+#!/bin/bash
+# Pre-removal script for one-kvm
+
+set -e
+
+case "$1" in
+    remove|purge)
+        # Stop service if running
+        if [ -d /run/systemd/system ]; then
+            systemctl stop one-kvm || true
+            systemctl disable one-kvm || true
+        fi
+        ;;
+    upgrade|deconfigure)
+        # Keep data on upgrade
+        :
+        ;;
+    failed-upgrade)
+        # Handle upgrade failure
+        :
+        ;;
+    *)
+        echo "prerm called with unknown argument: $1" >&2
+        exit 1
+        ;;
+esac
+
+exit 0