feat: 为 EasyTier 添加完整 TOML 配置支持

- 新增快速配置与完整配置模式，兼容旧版配置
 - 统一扩展配置校验及受保护临时文件生命周期
- 支持通过 easytier-core -c 加载 TOML 配置
- 复用前端配置模式编辑组件并更新中英文文案与类型
- 补充配置校验、启动参数、文件权限及清理测试

src/extensions/protected_config.rs

@@ -0,0 +1,95 @@
+use std::path::{Path, PathBuf};
+
+use tempfile::TempDir;
+
+pub(crate) struct ProtectedConfigFile {
+    _temp_dir: TempDir,
+    path: PathBuf,
+}
+
+impl ProtectedConfigFile {
+    pub(crate) async fn create(
+        extension_name: &str,
+        file_name: &str,
+        contents: &str,
+    ) -> Result<Self, String> {
+        let temp_dir = tempfile::tempdir().map_err(|error| {
+            format!("Failed to create {} config dir: {}", extension_name, error)
+        })?;
+        let path = temp_dir.path().join(file_name);
+
+        #[cfg(unix)]
+        {
+            use std::os::unix::fs::PermissionsExt;
+
+            std::fs::set_permissions(temp_dir.path(), std::fs::Permissions::from_mode(0o700))
+                .map_err(|error| {
+                    format!("Failed to protect {} config dir: {}", extension_name, error)
+                })?;
+        }
+
+        tokio::fs::write(&path, contents)
+            .await
+            .map_err(|error| format!("Failed to write {} config: {}", extension_name, error))?;
+
+        #[cfg(unix)]
+        {
+            use std::os::unix::fs::PermissionsExt;
+
+            tokio::fs::set_permissions(&path, std::fs::Permissions::from_mode(0o600))
+                .await
+                .map_err(|error| {
+                    format!("Failed to protect {} config: {}", extension_name, error)
+                })?;
+        }
+
+        Ok(Self {
+            _temp_dir: temp_dir,
+            path,
+        })
+    }
+
+    pub(crate) fn path(&self) -> &Path {
+        &self.path
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[tokio::test]
+    async fn protects_and_cleans_up_config_file() {
+        let config =
+            ProtectedConfigFile::create("Test extension", "extension.toml", "enabled = true\n")
+                .await
+                .unwrap();
+        let path = config.path().to_path_buf();
+
+        assert_eq!(
+            tokio::fs::read_to_string(&path).await.unwrap(),
+            "enabled = true\n"
+        );
+
+        #[cfg(unix)]
+        {
+            use std::os::unix::fs::PermissionsExt;
+
+            assert_eq!(
+                std::fs::metadata(path.parent().unwrap())
+                    .unwrap()
+                    .permissions()
+                    .mode()
+                    & 0o777,
+                0o700
+            );
+            assert_eq!(
+                std::fs::metadata(&path).unwrap().permissions().mode() & 0o777,
+                0o600
+            );
+        }
+
+        drop(config);
+        assert!(!path.exists());
+    }
+}