Fix CampusNAS recovery after VPN loss

Sources/CampusNASMonitor/AppModel.swift

@@ -50,6 +50,8 @@ final class AppModel: ObservableObject {
     private(set) var config: Config
     private var timer: Timer?
     private var checking = false
+    private var checkStartedAt: Date?
+    private var checkGeneration = 0
     /// Tracked separately from `state` so "just became reachable" can be told
     /// apart from "still reachable" when deciding to auto-mount.
     private var previousState: LinkState = .unknown
@@ -114,12 +116,24 @@ final class AppModel: ObservableObject {
 
     // MARK: - Probing
 
-    func checkNow() {
-        guard !checking else { return }
+    func checkNow(force: Bool = false) {
+        // A network framework call is supposed to be bounded, but defensive
+        // recovery matters here: one stuck check must not freeze the displayed
+        // state for days. Normal overlapping timer ticks are still ignored.
+        if checking && !force {
+            let age = checkStartedAt.map { Date().timeIntervalSince($0) } ?? 0
+            guard age > max(config.probeTimeoutSeconds * 3, 15) else { return }
+            Log.write("probe watchdog: replacing check stuck for \(Int(age)) s")
+        }
+
+        checkGeneration += 1
+        let generation = checkGeneration
         checking = true
+        checkStartedAt = Date()
 
         Task { @MainActor in
             let next = await probe()
+            guard generation == self.checkGeneration else { return }
             self.mounted = Mounter.mountedShares(host: config.nasHost)
 
             let wasUnknown = self.previousState == .unknown
@@ -131,6 +145,7 @@ final class AppModel: ObservableObject {
             self.previousState = next
             self.state = next
             self.checking = false
+            self.checkStartedAt = nil
 
             if notable { self.onNotableChange?(next) }
 
@@ -145,6 +160,13 @@ final class AppModel: ObservableObject {
         }
     }
 
+    /// Sleep invalidates tunnels and may pause run-loop timers. Re-probe as
+    /// soon as macOS wakes, superseding a check that started before sleep.
+    func wake() {
+        Log.write("system wake: refreshing VPN and NAS state")
+        checkNow(force: true)
+    }
+
     /// Explicit refresh always re-enumerates, unlike the polling path.
     func refreshAll() {
         Task { @MainActor in