Feed resilience, clearer empty states, and read/unread

- Don't blank the feed on refresh: keep current stories until new data
  arrives, and ignore benign URLError.cancelled (-999) so a network blip
  no longer wipes the list. Coalesce WebSocket story.created bursts into a
  single debounced refresh.
- Empty state now distinguishes polling, couldn't-reach-server (with the
  error + host + Retry), offline, and genuinely-empty.
- Track read stories in SwiftData (ReadStory); mark a story read when opened
  and drop/dim its signal stripe across the feed and Latest/Saved/Search.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Jarvis/Views/Home/SignalFeedView.swift

@@ -18,15 +18,18 @@ struct JarvisWordmark: View {
 struct SignalFeedView: View {
     @EnvironmentObject var store: StoryStore
     @EnvironmentObject var ws: WebSocketManager
+    @EnvironmentObject var settings: ServerSettings
     @Environment(\.modelContext) private var modelContext
 
     @Query private var cachedStories: [CachedStory]
     @Query private var cachedArticles: [CachedArticle]
+    @Query private var readStories: [ReadStory]
     @State private var showFeeds = false
     @State private var showSettings = false
 
     /// Stories that have full article content cached → eligible for the green dot.
     private var cachedStoryIds: Set<String> { Set(cachedArticles.map(\.storyId)) }
+    private var readStoryIds: Set<String> { Set(readStories.map(\.id)) }
 
     /// Live stories when online; cached fallback when the feed is empty & offline.
     private var displayStories: [StorySummary] {
@@ -175,7 +178,9 @@ struct SignalFeedView: View {
                 } else {
                     ForEach(displayStories) { story in
                         NavigationLink(value: story) {
-                            StoryRowView(story: story, isCached: cachedStoryIds.contains(story.id))
+                            StoryRowView(story: story,
+                                         isCached: cachedStoryIds.contains(story.id),
+                                         isRead: readStoryIds.contains(story.id))
                         }
                         .buttonStyle(.plain)
                         .onAppear {
@@ -201,20 +206,66 @@ struct SignalFeedView: View {
     private var emptyState: some View {
         VStack(spacing: 12) {
             if store.isLoading {
+                // Actively polling the server.
                 ProgressView().tint(Palette.orange)
+                Text("Polling signals…")
+                    .font(.system(size: 14, weight: .heavy))
+                    .foregroundStyle(Color(hex: "AAAAAA"))
+                hostLine
+            } else if let error = store.error {
+                // Reached the empty state because the fetch failed.
+                emptyIcon("exclamationmark.triangle", color: Color(hex: "C25555"))
+                Text("Couldn't reach the server")
+                    .font(.system(size: 15, weight: .heavy)).foregroundStyle(.white)
+                Text(error.errorDescription ?? "Unknown error")
+                    .font(.system(size: 12)).foregroundStyle(Color(hex: "888888"))
+                    .multilineTextAlignment(.center)
+                hostLine
+                refreshButton("Retry")
+            } else if !ws.connectionState.isLive {
+                emptyIcon("wifi.slash")
+                Text("Offline").font(.system(size: 15, weight: .heavy)).foregroundStyle(.white)
+                Text("No cached stories to show")
+                    .font(.system(size: 12)).foregroundStyle(Color(hex: "888888"))
+                refreshButton("Retry")
             } else {
-                Image(systemName: ws.connectionState.isLive ? "antenna.radiowaves.left.and.right" : "wifi.slash")
-                    .font(.system(size: 30))
-                    .foregroundStyle(Color(hex: "333333"))
-                Text(ws.connectionState.isLive ? "No signals yet" : "Offline — no cached stories")
-                    .font(.system(size: 14, weight: .bold))
-                    .foregroundStyle(Color(hex: "555555"))
+                // Connected, loaded, genuinely nothing yet.
+                emptyIcon("antenna.radiowaves.left.and.right")
+                Text("No signals yet").font(.system(size: 15, weight: .heavy)).foregroundStyle(.white)
+                Text("Pull to refresh")
+                    .font(.system(size: 12)).foregroundStyle(Color(hex: "888888"))
+                refreshButton("Refresh")
             }
         }
         .frame(maxWidth: .infinity)
+        .padding(.horizontal, 32)
         .padding(.top, 80)
     }
 
+    private func emptyIcon(_ name: String, color: Color = Color(hex: "333333")) -> some View {
+        Image(systemName: name).font(.system(size: 30)).foregroundStyle(color)
+    }
+
+    @ViewBuilder private var hostLine: some View {
+        if let host = settings.host {
+            Text(host)
+                .font(.system(size: 11, design: .monospaced))
+                .foregroundStyle(Color(hex: "555555"))
+        }
+    }
+
+    private func refreshButton(_ title: String) -> some View {
+        Button {
+            Task { await store.loadStories(refresh: true) }
+        } label: {
+            Text(title)
+                .font(.system(size: 14, weight: .bold)).foregroundStyle(.black)
+                .padding(.horizontal, 22).frame(height: 44)
+                .background(Palette.orange).clipShape(Capsule())
+        }
+        .padding(.top, 6)
+    }
+
     // MARK: - Caching
 
     private func cacheStories(_ stories: [StorySummary]) {