feat(macOS): add gateway password auth support and fix Swift 6.2 concurrency

- Add CLAWDIS_GATEWAY_PASSWORD to launchd plist environment
- Read password from gateway.remote.password config in client
- Fix Swift 6.2 sending parameter violations in config save functions
- Add password parameter to GatewayConnection.Config type
- GatewayChannel now sends password in connect auth params
- GatewayEndpointStore and GatewayLaunchAgentManager read password from config
- CLI gateway client reads password from remote config and env

apps/macos/Sources/Clawdis/ConfigStore.swift

@@ -43,7 +43,7 @@ enum ConfigStore {
     }
 
     @MainActor
-    static func save(_ root: [String: Any]) async throws {
+    static func save(_ root: sending [String: Any]) async throws {
         let overrides = await self.overrideStore.overrides
         if await self.isRemoteMode() {
             if let override = overrides.saveRemote {