Improve streaming interfaces and profile loading logic

Signed-off-by: Daniel D’Aquino <daniel@daquino.me>

damus/Core/Nostr/ProfileObserver.swift

@@ -0,0 +1,35 @@
+//
+//  ProfileObserver.swift
+//  damus
+//
+//  Created by Daniel D’Aquino on 2025-09-19.
+//
+import Combine
+import Foundation
+
+@MainActor
+class ProfileObserver: ObservableObject {
+    private let pubkey: Pubkey
+    private var observerTask: Task<Void, any Error>? = nil
+    private let damusState: DamusState
+    
+    init(pubkey: Pubkey, damusState: DamusState) {
+        self.pubkey = pubkey
+        self.damusState = damusState
+        self.watchProfileChanges()
+    }
+    
+    private func watchProfileChanges() {
+        observerTask?.cancel()
+        observerTask = Task {
+            for await _ in await damusState.nostrNetwork.profilesManager.streamProfile(pubkey: self.pubkey) {
+                try Task.checkCancellation()
+                DispatchQueue.main.async { self.objectWillChange.send() }
+            }
+        }
+    }
+    
+    deinit {
+        observerTask?.cancel()
+    }
+}