feat: Refactor account management to use SharedPreferences for last logged public key for immediate access

app/src/main/java/com/rosetta/messenger/ui/auth/UnlockScreen.kt

@@ -93,21 +93,30 @@ fun UnlockScreen(
             )
         }
         
-        // Select account - prioritize: selectedAccountId > lastLoggedPublicKey > first account
+        // Get last logged account from SharedPreferences (synchronous, reliable)
         val lastLoggedKey = accountManager.getLastLoggedPublicKey()
         
-        Log.d("UnlockScreen", "Loading accounts. selectedAccountId=$selectedAccountId, lastLoggedKey=$lastLoggedKey")
+        Log.d("UnlockScreen", "Loading accounts. lastLoggedKey=$lastLoggedKey")
         Log.d("UnlockScreen", "Available accounts: ${accounts.map { "${it.name}:${it.publicKey.take(8)}" }}")
         
-        // Find the target account
+        // Find the target account - prioritize selectedAccountId, then lastLoggedKey
         val targetAccount = when {
-            selectedAccountId != null -> accounts.find { it.publicKey == selectedAccountId }
-            lastLoggedKey != null -> accounts.find { it.publicKey == lastLoggedKey }
-            else -> null
+            selectedAccountId != null -> {
+                Log.d("UnlockScreen", "Using selectedAccountId: $selectedAccountId")
+                accounts.find { it.publicKey == selectedAccountId }
+            }
+            lastLoggedKey != null -> {
+                Log.d("UnlockScreen", "Using lastLoggedKey: ${lastLoggedKey.take(8)}")
+                accounts.find { it.publicKey == lastLoggedKey }
+            }
+            else -> {
+                Log.d("UnlockScreen", "No lastLoggedKey, using first account")
+                null
+            }
         }
         
         selectedAccount = targetAccount ?: accounts.firstOrNull()
-        Log.d("UnlockScreen", "Selected account: ${selectedAccount?.name}:${selectedAccount?.publicKey?.take(8)}")
+        Log.d("UnlockScreen", "Final selected: ${selectedAccount?.name}:${selectedAccount?.publicKey?.take(8)}")
     }
     
     // Filter accounts by search
@@ -136,8 +145,12 @@ fun UnlockScreen(
     // Auto-focus search when dropdown opens
     LaunchedEffect(isDropdownExpanded) {
         if (isDropdownExpanded) {
-            kotlinx.coroutines.delay(200)
-            searchFocusRequester.requestFocus()
+            kotlinx.coroutines.delay(300)
+            try {
+                searchFocusRequester.requestFocus()
+            } catch (e: Exception) {
+                // FocusRequester may not be attached yet, ignore
+            }
         } else {
             searchQuery = ""
         }