fix(multi-account): fetch metadata for all accounts, persist display names

Display names weren't showing because metadata was never requested for
account pubkeys. Now:

1. LaunchedEffect triggers loadMetadataForPubkeys() for all accounts
   in the switcher once relays connect
2. metadataVersion collector persists display names for ALL accounts
   (not just active one) when metadata arrives from relays
3. Names available immediately on next dropdown open

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

desktopApp/src/jvmMain/kotlin/com/vitorpamplona/amethyst/desktop/Main.kt

@@ -673,15 +673,37 @@ fun App(
         }
     }
 
-    // Persist display name when metadata arrives from relays (debounced)
+    // Fetch metadata for all accounts in the switcher + persist display names
+    val allAccountsForMetadata by accountManager.allAccounts.collectAsState()
+    LaunchedEffect(allAccountsForMetadata, accountState) {
+        if (accountState !is AccountState.LoggedIn) return@LaunchedEffect
+        // Wait for relay connections before requesting metadata
+        relayManager.connectedRelays.first { it.isNotEmpty() }
+        // Request metadata for all account pubkeys
+        val pubkeys =
+            allAccountsForMetadata.mapNotNull { info ->
+                com.vitorpamplona.quartz.nip19Bech32
+                    .decodePublicKeyAsHexOrNull(info.npub)
+            }
+        if (pubkeys.isNotEmpty()) {
+            subscriptionsCoordinator.loadMetadataForPubkeys(pubkeys)
+        }
+    }
+
+    // Persist display names when metadata arrives (debounced)
     LaunchedEffect(Unit) {
         localCache.metadataVersion.collect {
-            kotlinx.coroutines.delay(2000) // debounce — wait for batch of metadata to settle
-            val current = accountManager.currentAccount() ?: return@collect
-            val user = localCache.getUserIfExists(current.pubKeyHex) ?: return@collect
-            val name = user.toBestDisplayName()
-            if (name != user.pubkeyDisplayHex()) {
-                accountManager.updateDisplayName(current.npub, name)
+            kotlinx.coroutines.delay(3000)
+            val accounts = accountManager.allAccounts.value
+            for (info in accounts) {
+                val hex =
+                    com.vitorpamplona.quartz.nip19Bech32
+                        .decodePublicKeyAsHexOrNull(info.npub) ?: continue
+                val user = localCache.getUserIfExists(hex) ?: continue
+                val name = user.toBestDisplayName()
+                if (name != user.pubkeyDisplayHex() && name != info.displayName) {
+                    accountManager.updateDisplayName(info.npub, name)
+                }
             }
         }
     }