Don't accept input until slash commands are loaded (#11162)

packages/cli/src/ui/AppContainer.tsx

@@ -681,6 +681,7 @@ Logging in with Google... Please restart Gemini CLI to continue.
   const isInputActive =
     !initError &&
     !isProcessing &&
+    !!slashCommands &&
     (streamingState === StreamingState.Idle ||
       streamingState === StreamingState.Responding) &&
     !proQuotaRequest;