fix: compilation errors

- Fix OpenClawTheme call syntax in MainActivity
- Update ChatSheetTestHelper to use SessionHeader
- Fix all Kotlin compilation errors

Author: OpenCode Bot

openclaw-android/src/main/java/ai/openclaw/app/MainActivity.kt

@@ -53,7 +53,7 @@ class MainActivity : ComponentActivity() {
     }
 
     setContent {
-      OpenClawTheme {
+      OpenClawTheme() {
         Surface(modifier = Modifier) {
           RootScreen(viewModel = viewModel)
         }

openclaw-android/src/main/java/ai/openclaw/app/ui/chat/ChatSheetTestHelper.kt

@@ -4,23 +4,25 @@ import androidx.compose.runtime.Composable
 import ai.openclaw.app.chat.ChatSessionEntry
 
 /**
- * Test helper to expose internal ChatThreadSelector for UI testing.
+ * Test helper to expose internal SessionHeader for UI testing.
  */
 object ChatSheetTestHelper {
     @Composable
-    fun ChatThreadSelectorTest(
+    fun SessionHeaderTest(
         sessionKey: String,
         sessions: List<ChatSessionEntry>,
         mainSessionKey: String,
         onSelectSession: (String) -> Unit = {},
         onDeleteSession: ((String) -> Unit)? = null,
+        onNewSession: (() -> Unit)? = null,
     ) {
-        ChatThreadSelector(
+        SessionHeader(
             sessionKey = sessionKey,
             sessions = sessions,
             mainSessionKey = mainSessionKey,
             onSelectSession = onSelectSession,
             onDeleteSession = onDeleteSession,
+            onNewSession = onNewSession,
         )
     }
 }