feat(chess): add dismiss/clear-all for finished games in lobby

Persist dismissed game IDs locally (SharedPreferences on Android,
java.util.prefs on Desktop) so completed games can be permanently
hidden from the chess lobby. Adds per-game dismiss button and
"Clear all" action when 2+ finished games exist.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/chess/ChessDismissedGamesStorage.kt

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.commons.chess
+
+/**
+ * Persists dismissed chess game IDs locally per user.
+ * Uses expect/actual for platform-specific storage.
+ */
+expect class ChessDismissedGamesStorage private constructor() {
+    companion object {
+        fun create(context: Any? = null): ChessDismissedGamesStorage
+    }
+
+    fun load(userPubkey: String): Set<String>
+
+    fun save(
+        userPubkey: String,
+        ids: Set<String>,
+    )
+}

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/chess/ChessLobbyCards.kt

@@ -27,8 +27,12 @@ import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Close
 import androidx.compose.material3.Button
 import androidx.compose.material3.Card
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.OutlinedButton
 import androidx.compose.material3.Text
@@ -289,6 +293,7 @@ fun CompletedGameCard(
     isDraw: Boolean,
     moveCount: Int,
     onClick: (() -> Unit)? = null,
+    onDismiss: (() -> Unit)? = null,
     modifier: Modifier = Modifier,
     avatar: @Composable (() -> Unit)? = null,
 ) {
@@ -340,6 +345,15 @@ fun CompletedGameCard(
                 color = resultColor,
                 fontWeight = FontWeight.Bold,
             )
+            if (onDismiss != null) {
+                IconButton(onClick = onDismiss) {
+                    Icon(
+                        Icons.Default.Close,
+                        contentDescription = "Dismiss",
+                        tint = MaterialTheme.colorScheme.onSurfaceVariant,
+                    )
+                }
+            }
         }
     }
 }

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/chess/ChessLobbyLogic.kt

@@ -125,9 +125,15 @@ class ChessLobbyLogic(
     private val metadataProvider: IUserMetadataProvider,
     private val scope: CoroutineScope,
     pollingConfig: ChessPollingConfig = ChessPollingDefaults.android,
+    private val dismissedStorage: ChessDismissedGamesStorage? = null,
 ) {
     val state = ChessLobbyState(userPubkey, scope)
 
+    private val dismissedGameIds: MutableSet<String> =
+        java.util.Collections.synchronizedSet(
+            dismissedStorage?.load(userPubkey)?.toMutableSet() ?: mutableSetOf(),
+        )
+
     // Track when games were last loaded to prevent duplicate fetches
     // (e.g., discoverUserGames loads a game, then polling immediately re-fetches it)
     private val recentlyLoadedGames = java.util.concurrent.ConcurrentHashMap<String, Long>()
@@ -869,6 +875,7 @@ class ChessLobbyLogic(
 
         for (startEventId in newGameIds) {
             if (startEventId in completedGameIds) continue
+            if (startEventId in dismissedGameIds) continue
 
             val events = fetcher.fetchGameEvents(startEventId)
             val result = ChessGameLoader.loadGame(events, userPubkey)
@@ -942,6 +949,19 @@ class ChessLobbyLogic(
         return null
     }
 
+    fun dismissCompletedGame(gameId: String) {
+        state.removeCompletedGame(gameId)
+        dismissedGameIds.add(gameId)
+        dismissedStorage?.save(userPubkey, HashSet(dismissedGameIds))
+    }
+
+    fun dismissAllCompletedGames() {
+        val allIds = state.completedGames.value.map { it.gameId }
+        state.clearCompletedGames()
+        dismissedGameIds.addAll(allIds)
+        dismissedStorage?.save(userPubkey, HashSet(dismissedGameIds))
+    }
+
     /**
      * Dismiss a finished game from the active/spectating list and move it to completed.
      * Called when the user clicks "Continue" on the game end overlay, or automatically

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/chess/ChessLobbyState.kt

@@ -442,6 +442,16 @@ class ChessLobbyState(
         }
     }
 
+    fun removeCompletedGame(gameId: String) {
+        _completedGames.update { current ->
+            current.filter { it.gameId != gameId }
+        }
+    }
+
+    fun clearCompletedGames() {
+        _completedGames.value = emptyList()
+    }
+
     fun addSpectatingGame(
         gameId: String,
         state: LiveChessGameState,