refactor: expose my 31989s as a LocalCache-observed StateFlow on Account

Account.myAppRecommendations is now LocalCache.observeEvents (indexed
kind+author filter) stated in the account scope, seeded with a
synchronous scan so the editor's first frame still sorts correctly.
The editor and the Recommend button collect it instead of rescanning
the cache on every newEventBundles emission; isAppRecommended is gone.
The synchronous scan stays only as the seed and for the mutex-guarded
read-modify-write publishers, which must read current cache truth.

https://claude.ai/code/session_015dX5vWqvXUYD8rzPYX8vTB

amethyst/src/main/java/com/vitorpamplona/amethyst/model/Account.kt

@@ -1620,17 +1620,27 @@ class Account(
      */
     private val appRecommendationsMutex = Mutex()
 
+    /**
+     * Synchronous cache scan, used to seed [myAppRecommendations] and by the
+     * read-modify-write publishers below, which must read current truth from
+     * the cache while holding [appRecommendationsMutex].
+     */
     fun myAppRecommendationEvents(): List<AppRecommendationEvent> =
         cache.addressables
             .filterIntoSet(AppRecommendationEvent.KIND, signer.pubKey)
             .mapNotNull { it.event as? AppRecommendationEvent }
 
-    fun isAppRecommended(app: AppDefinitionEvent): Boolean {
-        val address = app.addressTag()
-        return myAppRecommendationEvents().any { event ->
-            event.recommendationAddresses().any { it == address }
-        }
-    }
+    /**
+     * My kind 31989 recommendation events (one per handled kind), kept in
+     * sync as the cache consumes new versions. UI should collect this
+     * instead of rescanning the cache on every event bundle.
+     */
+    val myAppRecommendations: StateFlow<List<AppRecommendationEvent>> =
+        cache
+            .observeEvents<AppRecommendationEvent>(
+                Filter(kinds = listOf(AppRecommendationEvent.KIND), authors = listOf(signer.pubKey)),
+            ).flowOn(Dispatchers.IO)
+            .stateIn(scope, SharingStarted.WhileSubscribed(30000), myAppRecommendationEvents())
 
     /**
      * Returns a createdAt strictly greater than whatever AppRecommendationEvent

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/types/AppDefinition.kt

@@ -52,7 +52,6 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
-import androidx.compose.runtime.produceState
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.setValue
@@ -69,12 +68,12 @@ import androidx.compose.ui.text.font.FontFamily
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import coil3.compose.AsyncImage
 import com.vitorpamplona.amethyst.R
 import com.vitorpamplona.amethyst.commons.model.EmptyTagList
 import com.vitorpamplona.amethyst.commons.model.toImmutableListOfLists
 import com.vitorpamplona.amethyst.commons.richtext.RichTextParser
-import com.vitorpamplona.amethyst.model.LocalCache
 import com.vitorpamplona.amethyst.model.Note
 import com.vitorpamplona.amethyst.ui.components.ClickableTextPrimary
 import com.vitorpamplona.amethyst.ui.components.CreateTextWithEmoji
@@ -97,7 +96,6 @@ import com.vitorpamplona.quartz.nip01Core.core.HexKey
 import com.vitorpamplona.quartz.nip89AppHandlers.PlatformType
 import com.vitorpamplona.quartz.nip89AppHandlers.definition.AppDefinitionEvent
 import com.vitorpamplona.quartz.nip89AppHandlers.definition.AppMetadata
-import com.vitorpamplona.quartz.nip89AppHandlers.recommendation.AppRecommendationEvent
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
@@ -431,16 +429,13 @@ private fun RecommendAppButton(
     note: Note,
     accountViewModel: AccountViewModel,
 ) {
-    val myPubkey = accountViewModel.userProfile().pubkeyHex
+    val myRecommendations by accountViewModel.account.myAppRecommendations.collectAsStateWithLifecycle()
 
-    val isRecommended by
-        produceState(initialValue = false, key1 = noteEvent) {
-            value = withContext(Dispatchers.IO) { accountViewModel.account.isAppRecommended(noteEvent) }
-            LocalCache.live.newEventBundles.collect { bundle ->
-                val touchesMine = bundle.any { (it.event as? AppRecommendationEvent)?.pubKey == myPubkey }
-                if (touchesMine) {
-                    value = withContext(Dispatchers.IO) { accountViewModel.account.isAppRecommended(noteEvent) }
-                }
+    val isRecommended =
+        remember(myRecommendations, noteEvent) {
+            val address = noteEvent.addressTag()
+            myRecommendations.any { event ->
+                event.recommendationAddresses().any { it == address }
             }
         }
 

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/apps/recommendations/ProfileAppRecommendationsScreen.kt

@@ -68,7 +68,6 @@ import com.vitorpamplona.amethyst.ui.screen.loggedIn.apps.recommendations.dataso
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.relays.kindDisplayName
 import com.vitorpamplona.amethyst.ui.stringRes
 import com.vitorpamplona.quartz.nip89AppHandlers.definition.AppDefinitionEvent
-import com.vitorpamplona.quartz.nip89AppHandlers.recommendation.AppRecommendationEvent
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
 
@@ -83,31 +82,22 @@ fun ProfileAppRecommendationsScreen(
     // relays so the list below has candidates while this screen is open.
     ProfileAppRecommendationsFilterAssemblerSubscription(accountViewModel)
 
-    // Ticks whenever LocalCache emits a bundle that touches my recommendations
-    // or any app definition, so the snapshots below recompute.
-    var recommendationsTick by remember { mutableIntStateOf(0) }
+    // Ticks whenever LocalCache emits a bundle with a new app definition, so
+    // the candidate snapshot below recomputes.
     var appDefinitionsTick by remember { mutableIntStateOf(0) }
     LaunchedEffect(myPubkey) {
         launch(Dispatchers.IO) {
             LocalCache.live.newEventBundles.collect { bundle ->
-                var newRecommendations = false
-                var newDefinitions = false
-                bundle.forEach { note ->
-                    val event = note.event
-                    if (event is AppRecommendationEvent && event.pubKey == myPubkey) newRecommendations = true
-                    if (event is AppDefinitionEvent) newDefinitions = true
-                }
-                if (newRecommendations) recommendationsTick++
-                if (newDefinitions) appDefinitionsTick++
+                if (bundle.any { it.event is AppDefinitionEvent }) appDefinitionsTick++
             }
         }
     }
 
+    val myRecommendationEvents by accountViewModel.account.myAppRecommendations.collectAsStateWithLifecycle()
+
     val recommendedAddresses =
-        remember(recommendationsTick) {
-            accountViewModel.account
-                .myAppRecommendationEvents()
-                .flatMapTo(mutableSetOf()) { event -> event.recommendations().map { it.address } }
+        remember(myRecommendationEvents) {
+            myRecommendationEvents.flatMapTo(mutableSetOf()) { event -> event.recommendations().map { it.address } }
         }
 
     // The recommended set used for ORDERING only. It tracks recommendedAddresses