feat(macos): add direct gateway transport

apps/macos/Sources/Clawdbot/GatewayDiscoveryHelpers.swift

@@ -0,0 +1,47 @@
+import ClawdbotDiscovery
+import Foundation
+
+enum GatewayDiscoveryHelpers {
+    static func sshTarget(for gateway: GatewayDiscoveryModel.DiscoveredGateway) -> String? {
+        let host = self.sanitizedTailnetHost(gateway.tailnetDns) ?? gateway.lanHost
+        guard let host = self.trimmed(host), !host.isEmpty else { return nil }
+        let user = NSUserName()
+        var target = "\(user)@\(host)"
+        if gateway.sshPort != 22 {
+            target += ":\(gateway.sshPort)"
+        }
+        return target
+    }
+
+    static func directUrl(for gateway: GatewayDiscoveryModel.DiscoveredGateway) -> String? {
+        self.directGatewayUrl(
+            tailnetDns: gateway.tailnetDns,
+            lanHost: gateway.lanHost,
+            gatewayPort: gateway.gatewayPort)
+    }
+
+    static func directGatewayUrl(
+        tailnetDns: String?,
+        lanHost: String?,
+        gatewayPort: Int?) -> String?
+    {
+        if let tailnetDns = self.sanitizedTailnetHost(tailnetDns) {
+            return "wss://\(tailnetDns)"
+        }
+        guard let lanHost = self.trimmed(lanHost), !lanHost.isEmpty else { return nil }
+        let port = gatewayPort ?? 18789
+        return "ws://\(lanHost):\(port)"
+    }
+
+    static func sanitizedTailnetHost(_ host: String?) -> String? {
+        guard let host = self.trimmed(host), !host.isEmpty else { return nil }
+        if host.hasSuffix(".internal.") || host.hasSuffix(".internal") {
+            return nil
+        }
+        return host
+    }
+
+    private static func trimmed(_ value: String?) -> String? {
+        value?.trimmingCharacters(in: .whitespacesAndNewlines)
+    }
+}