Default 'enable-audio' to off via custom.txt (read by Rust load_custom_client)

- Added flutter/macos/Runner/custom.txt with default-settings.enable-audio=N
- Added custom.txt to Xcode Copy Bundle Resources (PBXResourcesBuildPhase)
- RustDesk's load_custom_client() reads this file and injects into DEFAULT_SETTINGS
- Users can still toggle 'Enable audio' in Settings; this just flips the default

This addresses the user's request to disable all 4 audio behaviors by default
(play remote sound, hear remote mic, voice call, capture host audio), all of
which share the single 'enable-audio' option.

flutter/macos/Runner.xcodeproj/project.pbxproj

@@ -26,6 +26,7 @@
 		33CC10F62044A3C60003C045 /* MainMenu.xib in Resources */ = {isa = PBXBuildFile; fileRef = 33CC10F42044A3C60003C045 /* MainMenu.xib */; };
 		33CC11132044BFA00003C045 /* MainFlutterWindow.swift in Sources */ = {isa = PBXBuildFile; fileRef = 33CC11122044BFA00003C045 /* MainFlutterWindow.swift */; };
 		7ED2B35F2BB007420099885C /* AppIcon.icns in Resources */ = {isa = PBXBuildFile; fileRef = 7ED2B35E2BB007420099885C /* AppIcon.icns */; };
+		AABBCC000100000000000001 /* custom.txt in Resources */ = {isa = PBXBuildFile; fileRef = AABBCC000200000000000002 /* custom.txt */; };
 		84010BA8292CF66600152837 /* liblibrustdesk.dylib in Frameworks */ = {isa = PBXBuildFile; fileRef = 84010BA7292CF66600152837 /* liblibrustdesk.dylib */; settings = {ATTRIBUTES = (Weak, ); }; };
 		84010BA9292CF68300152837 /* liblibrustdesk.dylib in Embed Libraries */ = {isa = PBXBuildFile; fileRef = 84010BA7292CF66600152837 /* liblibrustdesk.dylib */; settings = {ATTRIBUTES = (CodeSignOnCopy, ); }; };
 		C5E54335B73C89F72DB1B606 /* Pods_Runner.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 26C84465887F29AE938039CB /* Pods_Runner.framework */; };
@@ -75,6 +76,7 @@
 		7436B85D94E8F7B5A9324869 /* Pods-Runner.debug.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-Runner.debug.xcconfig"; path = "Target Support Files/Pods-Runner/Pods-Runner.debug.xcconfig"; sourceTree = "<group>"; };
 		7AFA3C8E1D35360C0083082E /* Release.xcconfig */ = {isa = PBXFileReference; lastKnownFileType = text.xcconfig; path = Release.xcconfig; sourceTree = "<group>"; };
 		7ED2B35E2BB007420099885C /* AppIcon.icns */ = {isa = PBXFileReference; lastKnownFileType = image.icns; name = AppIcon.icns; path = Runner/AppIcon.icns; sourceTree = "<group>"; };
+		AABBCC000200000000000002 /* custom.txt */ = {isa = PBXFileReference; lastKnownFileType = text; name = custom.txt; path = Runner/custom.txt; sourceTree = "<group>"; };
 		84010BA7292CF66600152837 /* liblibrustdesk.dylib */ = {isa = PBXFileReference; lastKnownFileType = "compiled.mach-o.dylib"; name = liblibrustdesk.dylib; path = ../../target/release/liblibrustdesk.dylib; sourceTree = "<group>"; };
 		9740EEB21CF90195004384FC /* Debug.xcconfig */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.xcconfig; path = Debug.xcconfig; sourceTree = "<group>"; };
 		C3BB669FF6190AE1B11BCAEA /* Pods-Runner.profile.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-Runner.profile.xcconfig"; path = "Target Support Files/Pods-Runner/Pods-Runner.profile.xcconfig"; sourceTree = "<group>"; };
@@ -133,6 +135,7 @@
 				7ED2B35E2BB007420099885C /* AppIcon.icns */,
 				33CC10F42044A3C60003C045 /* MainMenu.xib */,
 				33CC10F72044A3C60003C045 /* Info.plist */,
+				AABBCC000200000000000002 /* custom.txt */,
 			);
 			name = Resources;
 			path = ..;
@@ -265,6 +268,7 @@
 			files = (
 				33CC10F62044A3C60003C045 /* MainMenu.xib in Resources */,
 				7ED2B35F2BB007420099885C /* AppIcon.icns in Resources */,
+				AABBCC000100000000000001 /* custom.txt in Resources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};

flutter/macos/Runner/custom.txt

@@ -0,0 +1,6 @@
+{
+  "app-name": "RustDesk",
+  "default-settings": {
+    "enable-audio": "N"
+  }
+}