refactor(runtime): remove redundant mode guard

ShadowsocksX-NG2/App/Application/ProxyControlWorkflow/ProxyControlWorkflow.swift

@@ -248,7 +248,7 @@ final class ProxyControlWorkflow: ObservableObject {
     return republish()
   }
 
-  /// 切换代理模式：可用性与 no-op 语义由控制器既有入口裁定；
+  /// 切换代理模式：no-op 语义由控制器既有入口裁定；
   /// 完成后整体重发布。持久化失败保留旧模式，失败以 typed fact 呈现。
   @discardableResult
   func setProxyMode(_ mode: ProxyMode) async -> ProxyControlSnapshot {

ShadowsocksX-NG2/App/Application/ProxyRuntime/ProxyRuntimeController+Mode.swift

@@ -5,7 +5,6 @@ extension ProxyRuntimeController {
   /// and global) also deploy and verify the ACL runtime even when system proxy
   /// is off, because manually connected SOCKS and HTTP clients use the same ACL.
   func setProxyMode(_ mode: ProxyMode) async {
-    guard ProxyMode.availableModes.contains(mode) else { return }
     guard mode != proxyMode else { return }
     await transitionMode(mode, ruleDefaultAction: settings.ruleDefaultAction)
   }

ShadowsocksX-NG2/Tests/ProxyControl/ProxyModeAvailabilityTests.swift

@@ -3,8 +3,7 @@ import XCTest
 
 @testable import ShadowsocksX_NG2
 
-/// Domain mode availability is the single policy shared by the menu and
-/// runtime mode entry points.
+/// Built-in modes keep a stable selector order and project local proxy settings.
 final class ProxyModeAvailabilityTests: XCTestCase {
   func testBuiltInModesAreAlwaysAvailableInProductOrder() {
     XCTAssertEqual(