🤖 Fix UI freeze when sending message in SSH workspaces (#450)

The UI froze for ~1s when sending messages in SSH workspaces because the
frontend awaited the entire IPC call, including remote temp directory
creation.

## Solution

Changed `ChatInput` to clear input/images immediately before the IPC
call instead of after it succeeds. This makes the UI responsive while
the backend handles SSH operations asynchronously.

On error, the previous state is restored so users can retry.

## Testing

Tested locally with SSH workspace - input clears immediately and chat
remains responsive during message send.

_Generated with `cmux`_

Author: ammar-agent

src/components/ChatInput.tsx

@@ -528,6 +528,9 @@ export const ChatInput: React.FC<ChatInputProps> = ({
       // Regular message - send directly via API
       setIsSending(true);
 
+      // Save current state for restoration on error
+      const previousImageAttachments = [...imageAttachments];
+
       try {
         // Prepare image parts if any
         const imageParts = imageAttachments.map((img, index) => {
@@ -583,6 +586,15 @@ export const ChatInput: React.FC<ChatInputProps> = ({
           }
         }
 
+        // Clear input and images immediately for responsive UI
+        // These will be restored if the send operation fails
+        setInput("");
+        setImageAttachments([]);
+        // Reset textarea height
+        if (inputRef.current) {
+          inputRef.current.style.height = "36px";
+        }
+
         const result = await window.api.workspace.sendMessage(workspaceId, actualMessageText, {
           ...sendMessageOptions,
           ...compactionOptions,
@@ -596,19 +608,13 @@ export const ChatInput: React.FC<ChatInputProps> = ({
           console.error("Failed to send message:", result.error);
           // Show error using enhanced toast
           setToast(createErrorToast(result.error));
-          // Restore input on error so user can try again
+          // Restore input and images on error so user can try again
           setInput(messageText);
+          setImageAttachments(previousImageAttachments);
         } else {
           // Track telemetry for successful message send
           telemetry.messageSent(sendMessageOptions.model, mode, actualMessageText.length);
 
-          // Success - clear input and images
-          setInput("");
-          setImageAttachments([]);
-          // Reset textarea height
-          if (inputRef.current) {
-            inputRef.current.style.height = "36px";
-          }
           // Exit editing mode if we were editing
           if (editingMessage && onCancelEdit) {
             onCancelEdit();
@@ -625,6 +631,7 @@ export const ChatInput: React.FC<ChatInputProps> = ({
           })
         );
         setInput(messageText);
+        setImageAttachments(previousImageAttachments);
       } finally {
         setIsSending(false);
       }