feat(discovery): gateway bonjour + node pairing bridge

apps/macos/Sources/Clawdis/MasterDiscoveryModel.swift

@@ -0,0 +1,103 @@
+import Foundation
+import Network
+
+@MainActor
+final class MasterDiscoveryModel: ObservableObject {
+    struct DiscoveredMaster: Identifiable, Equatable {
+        var id: String { self.debugID }
+        var displayName: String
+        var lanHost: String?
+        var tailnetDns: String?
+        var sshPort: Int
+        var debugID: String
+    }
+
+    @Published var masters: [DiscoveredMaster] = []
+    @Published var statusText: String = "Idle"
+
+    private var browser: NWBrowser?
+
+    private static let serviceType = "_clawdis-master._tcp"
+    private static let serviceDomain = "local."
+
+    func start() {
+        if self.browser != nil { return }
+
+        let params = NWParameters.tcp
+        params.includePeerToPeer = true
+
+        let browser = NWBrowser(for: .bonjour(type: Self.serviceType, domain: Self.serviceDomain), using: params)
+
+        browser.stateUpdateHandler = { [weak self] state in
+            Task { @MainActor in
+                guard let self else { return }
+                switch state {
+                case .setup:
+                    self.statusText = "Setup"
+                case .ready:
+                    self.statusText = "Searching…"
+                case let .failed(err):
+                    self.statusText = "Failed: \(err)"
+                case .cancelled:
+                    self.statusText = "Stopped"
+                case let .waiting(err):
+                    self.statusText = "Waiting: \(err)"
+                @unknown default:
+                    self.statusText = "Unknown"
+                }
+            }
+        }
+
+        browser.browseResultsChangedHandler = { [weak self] results, _ in
+            Task { @MainActor in
+                guard let self else { return }
+                self.masters = results.compactMap { result -> DiscoveredMaster? in
+                    guard case let .service(name, _, _, _) = result.endpoint else { return nil }
+
+                    var lanHost: String?
+                    var tailnetDns: String?
+                    var sshPort = 22
+                    if case let .bonjour(txt) = result.metadata {
+                        let dict = txt.dictionary
+                        if let value = dict["lanHost"] {
+                            let trimmed = value.trimmingCharacters(in: .whitespacesAndNewlines)
+                            lanHost = trimmed.isEmpty ? nil : trimmed
+                        }
+                        if let value = dict["tailnetDns"] {
+                            let trimmed = value.trimmingCharacters(in: .whitespacesAndNewlines)
+                            tailnetDns = trimmed.isEmpty ? nil : trimmed
+                        }
+                        if let value = dict["sshPort"],
+                           let parsed = Int(value.trimmingCharacters(in: .whitespacesAndNewlines)),
+                           parsed > 0
+                        {
+                            sshPort = parsed
+                        }
+                    }
+
+                    return DiscoveredMaster(
+                        displayName: name,
+                        lanHost: lanHost,
+                        tailnetDns: tailnetDns,
+                        sshPort: sshPort,
+                        debugID: Self.prettyEndpointDebugID(result.endpoint))
+                }
+                .sorted { $0.displayName.localizedCaseInsensitiveCompare($1.displayName) == .orderedAscending }
+            }
+        }
+
+        self.browser = browser
+        browser.start(queue: DispatchQueue(label: "com.steipete.clawdis.macos.master-discovery"))
+    }
+
+    func stop() {
+        self.browser?.cancel()
+        self.browser = nil
+        self.masters = []
+        self.statusText = "Stopped"
+    }
+
+    private static func prettyEndpointDebugID(_ endpoint: NWEndpoint) -> String {
+        String(describing: endpoint)
+    }
+}