feat(cache): Phase 3 — route all screen events through cache

All screens now pipe relay events into DesktopLocalCache via
coordinator.consumeEvent(). Existing per-screen EventCollectionState
kept for rendering (incremental migration), but data also enters
cache for persistence across navigation.

- FeedScreen: route global + following feed events
- ThreadScreen: route root note + reply events
- UserProfileScreen: route posts + add cache hydration on mount
  (LaunchedEffect queries cache for existing posts → instant display)
- BookmarksScreen: route public + private bookmark events
- ReadsScreen: route long-form feed events (add coordinator param)
- NotificationsScreen: route notification events

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

desktopApp/src/jvmMain/kotlin/com/vitorpamplona/amethyst/desktop/ui/BookmarksScreen.kt

@@ -188,7 +188,8 @@ fun BookmarksScreen(
                         FilterBuilders.byIds(publicBookmarkIds),
                     ),
                 relays = connectedRelays,
-                onEvent = { event, _, _, _ ->
+                onEvent = { event, _, relay, _ ->
+                    subscriptionsCoordinator?.consumeEvent(event, relay)
                     publicEventState.addItem(event)
                 },
                 onEose = { _, _ -> },
@@ -209,7 +210,8 @@ fun BookmarksScreen(
                         FilterBuilders.byIds(privateBookmarkIds),
                     ),
                 relays = connectedRelays,
-                onEvent = { event, _, _, _ ->
+                onEvent = { event, _, relay, _ ->
+                    subscriptionsCoordinator?.consumeEvent(event, relay)
                     privateEventState.addItem(event)
                 },
                 onEose = { _, _ -> },

desktopApp/src/jvmMain/kotlin/com/vitorpamplona/amethyst/desktop/ui/FeedScreen.kt

@@ -279,7 +279,8 @@ fun FeedScreen(
             FeedMode.GLOBAL -> {
                 createGlobalFeedSubscription(
                     relays = configuredRelays,
-                    onEvent = { event, _, _, _ ->
+                    onEvent = { event, _, relay, _ ->
+                        subscriptionsCoordinator?.consumeEvent(event, relay)
                         // Store metadata events in cache
                         if (event is MetadataEvent) {
                             localCache.consumeMetadata(event)

desktopApp/src/jvmMain/kotlin/com/vitorpamplona/amethyst/desktop/ui/NotificationsScreen.kt

@@ -143,7 +143,8 @@ fun NotificationsScreen(
             createNotificationsSubscription(
                 relays = connectedRelays,
                 pubKeyHex = account.pubKeyHex,
-                onEvent = { event, _, _, _ ->
+                onEvent = { event, _, relay, _ ->
+                    subscriptionsCoordinator?.consumeEvent(event, relay)
                     // Skip events from the user themselves (except zaps)
                     if (event.pubKey == account.pubKeyHex && event !is LnZapEvent) {
                         return@createNotificationsSubscription

desktopApp/src/jvmMain/kotlin/com/vitorpamplona/amethyst/desktop/ui/ReadsScreen.kt

@@ -62,6 +62,7 @@ import com.vitorpamplona.amethyst.commons.ui.components.LoadingState
 import com.vitorpamplona.amethyst.desktop.account.AccountState
 import com.vitorpamplona.amethyst.desktop.cache.DesktopLocalCache
 import com.vitorpamplona.amethyst.desktop.network.DesktopRelayConnectionManager
+import com.vitorpamplona.amethyst.desktop.subscriptions.DesktopRelaySubscriptionsCoordinator
 import com.vitorpamplona.amethyst.desktop.subscriptions.FeedMode
 import com.vitorpamplona.amethyst.desktop.subscriptions.createContactListSubscription
 import com.vitorpamplona.amethyst.desktop.subscriptions.createFollowingLongFormFeedSubscription
@@ -180,6 +181,7 @@ fun ReadsScreen(
     localCache: DesktopLocalCache,
     account: AccountState.LoggedIn? = null,
     nwcConnection: Nip47WalletConnect.Nip47URINorm? = null,
+    subscriptionsCoordinator: DesktopRelaySubscriptionsCoordinator? = null,
     onNavigateToProfile: (String) -> Unit = {},
     onNavigateToArticle: (String) -> Unit = {},
     onNavigateToThread: (String) -> Unit = {},
@@ -239,7 +241,8 @@ fun ReadsScreen(
             FeedMode.GLOBAL -> {
                 createLongFormFeedSubscription(
                     relays = connectedRelays,
-                    onEvent = { event, _, _, _ ->
+                    onEvent = { event, _, relay, _ ->
+                        subscriptionsCoordinator?.consumeEvent(event, relay)
                         if (event is LongTextNoteEvent) {
                             eventState.addItem(event)
                         }

desktopApp/src/jvmMain/kotlin/com/vitorpamplona/amethyst/desktop/ui/ThreadScreen.kt

@@ -203,7 +203,8 @@ fun ThreadScreen(
             createNoteSubscription(
                 relays = connectedRelays,
                 noteId = noteId,
-                onEvent = { event, _, _, _ ->
+                onEvent = { event, _, relay, _ ->
+                    subscriptionsCoordinator?.consumeEvent(event, relay)
                     if (event.id == noteId) {
                         rootNote = event
                         levelCache[event.id] = 0
@@ -224,7 +225,8 @@ fun ThreadScreen(
             createThreadRepliesSubscription(
                 relays = connectedRelays,
                 noteId = noteId,
-                onEvent = { event, _, _, _ ->
+                onEvent = { event, _, relay, _ ->
+                    subscriptionsCoordinator?.consumeEvent(event, relay)
                     replyEventState.addItem(event)
                 },
                 onEose = { _, _ ->

desktopApp/src/jvmMain/kotlin/com/vitorpamplona/amethyst/desktop/ui/UserProfileScreen.kt

@@ -206,13 +206,26 @@ fun UserProfileScreen(
         }
     }
 
-    // Clear posts when profile changes
+    // Clear posts when profile changes, then hydrate from cache
     remember(pubKeyHex, retryTrigger) {
         eventState.clear()
         postsLoading = true
         postsError = null
     }
 
+    // Hydrate from cache — show previously loaded posts instantly
+    LaunchedEffect(pubKeyHex) {
+        val cachedNotes =
+            localCache.notes.filterIntoSet { _, note ->
+                note.event?.kind == 1 && note.author?.pubkeyHex == pubKeyHex
+            }
+        if (cachedNotes.isNotEmpty()) {
+            val events = cachedNotes.mapNotNull { it.event }
+            eventState.addItems(events)
+            postsLoading = false
+        }
+    }
+
     // Subscribe to user metadata
     rememberSubscription(connectedRelays, pubKeyHex, retryTrigger, relayManager = relayManager) {
         if (connectedRelays.isNotEmpty()) {
@@ -308,7 +321,8 @@ fun UserProfileScreen(
             createUserPostsSubscription(
                 relays = connectedRelays,
                 pubKeyHex = pubKeyHex,
-                onEvent = { event, _, _, _ ->
+                onEvent = { event, _, relay, _ ->
+                    subscriptionsCoordinator?.consumeEvent(event, relay)
                     eventState.addItem(event)
                 },
                 onEose = { _, _ ->