Launch Activity Logic

Nucleic-Session: EBB24271-3AB2-4CBD-A47A-59FC73500371
Co-authored-by: Nucleic <[email protected]>

NucleicRemote/NucleicRemote/LiveActivityManager.swift

@@ -189,6 +189,41 @@ final class LiveActivityManager {
         enqueue(state)
     }
 
+    /// Start the process-lived observers that make push-to-start work: the device's push-to-start
+    /// token (forwarded to the Macs so they can create the glance over APNs) and adoption of any
+    /// Activity a Mac push-started while the app was closed. Idempotent — safe to call on every
+    /// bridge setup; the guards keep a single observer each.
+    func beginPushToStartObservation() {
+        guard ActivityAuthorizationInfo().areActivitiesEnabled else { return }
+        if pushToStartObservation == nil {
+            pushToStartObservation = Task { [weak self] in
+                for await data in Activity<NucleicSessionAttributes>.pushToStartTokenUpdates {
+                    let hex = data.map { String(format: "%02x", $0) }.joined()
+                    self?.onPushToStartToken?(hex)
+                }
+            }
+        }
+        if activityAdoptionObservation == nil {
+            activityAdoptionObservation = Task { [weak self] in
+                for await activity in Activity<NucleicSessionAttributes>.activityUpdates {
+                    self?.adopt(activity)
+                }
+            }
+        }
+    }
+
+    /// Adopt an Activity we didn't create locally — almost always one a Mac push-started while the
+    /// app was closed. Taking ownership wires up its update-token stream (`observePushToken`) so the
+    /// Macs can keep the glance fresh the normal way, and collapses any strays to one. If we already
+    /// track an Activity, leave it: the local `Activity.request` path and `endStrays` already keep a
+    /// single glance, and re-adopting would just churn the token observation.
+    private func adopt(_ activity: Activity<NucleicSessionAttributes>) {
+        guard self.activity == nil else { return }
+        self.activity = activity
+        observePushToken(activity)
+        endStrays(keeping: activity.id)
+    }
+
     /// Forward the activity's APNS update token (and its rotations) to `RemoteStore`.
     private func observePushToken(_ activity: Activity<NucleicSessionAttributes>) {
         tokenObservation?.cancel()