feat(frontend): display submitted question below input (sub-phase 2.2)

Show submitted question as italic text below the input area after clicking submit. Clears when user starts typing a new question.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

frontend/src/components/QueryInput.tsx

@@ -7,12 +7,14 @@ export interface QueryInputProps {
 
 export const QueryInput: React.FC<QueryInputProps> = ({ onSubmit, isLoading }) => {
   const [question, setQuestion] = useState<string>('')
+  const [submittedQuestion, setSubmittedQuestion] = useState<string | null>(null)
 
   const handleSubmit = (e: FormEvent): void => {
     e.preventDefault()
     const trimmed = question.trim()
     if (trimmed && !isLoading) {
       onSubmit(trimmed)
+      setSubmittedQuestion(trimmed)
       setQuestion('')
     }
   }
@@ -24,26 +26,40 @@ export const QueryInput: React.FC<QueryInputProps> = ({ onSubmit, isLoading }) =
     }
   }
 
+  const handleChange = (e: React.ChangeEvent<HTMLTextAreaElement>): void => {
+    setQuestion(e.target.value)
+    if (e.target.value.trim() !== '') {
+      setSubmittedQuestion(null)
+    }
+  }
+
   const isDisabled = isLoading || question.trim() === ''
 
   return (
     <form onSubmit={handleSubmit} className="space-y-3">
       <textarea
         value={question}
-        onChange={(e) => setQuestion(e.target.value)}
+        onChange={handleChange}
         onKeyDown={handleKeyDown}
         placeholder="Ask a question about your documents..."
         disabled={isLoading}
         rows={3}
         className="w-full rounded border border-gray-300 px-3 py-2 focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent disabled:bg-gray-100 disabled:cursor-not-allowed"
       />
-      <button
-        type="submit"
-        disabled={isDisabled}
-        className="px-4 py-2 bg-blue-600 text-white font-medium rounded hover:bg-blue-700 focus:outline-none focus:ring-2 focus:ring-blue-500 focus:ring-offset-2 disabled:opacity-50 disabled:cursor-not-allowed disabled:hover:bg-blue-600 transition-all duration-200"
-      >
-        {isLoading ? 'Processing...' : 'Submit'}
-      </button>
+      <div className="flex items-start gap-3">
+        <button
+          type="submit"
+          disabled={isDisabled}
+          className="px-4 py-2 bg-blue-600 text-white font-medium rounded hover:bg-blue-700 focus:outline-none focus:ring-2 focus:ring-blue-500 focus:ring-offset-2 disabled:opacity-50 disabled:cursor-not-allowed disabled:hover:bg-blue-600 transition-all duration-200"
+        >
+          {isLoading ? 'Processing...' : 'Submit'}
+        </button>
+      </div>
+      {submittedQuestion && (
+        <p data-testid="submitted-question" className="text-sm text-gray-500 italic">
+          Your question: &ldquo;{submittedQuestion}&rdquo;
+        </p>
+      )}
     </form>
   )
 }

frontend/src/test/components/QueryInput.test.tsx

@@ -111,4 +111,46 @@ describe('QueryInput', () => {
 
     expect(mockOnSubmit).not.toHaveBeenCalled()
   })
+
+  it('shows submitted question after clicking submit', () => {
+    render(<QueryInput onSubmit={mockOnSubmit} isLoading={false} />)
+    const textarea = screen.getByPlaceholderText('Ask a question about your documents...')
+    const button = screen.getByRole('button', { name: /submit/i })
+
+    fireEvent.change(textarea, { target: { value: 'What is NEC4?' } })
+    fireEvent.click(button)
+
+    expect(screen.getByTestId('submitted-question')).toHaveTextContent('What is NEC4?')
+  })
+
+  it('clears submitted question when user starts typing a new question', () => {
+    render(<QueryInput onSubmit={mockOnSubmit} isLoading={false} />)
+    const textarea = screen.getByPlaceholderText('Ask a question about your documents...')
+    const button = screen.getByRole('button', { name: /submit/i })
+
+    fireEvent.change(textarea, { target: { value: 'First question' } })
+    fireEvent.click(button)
+    expect(screen.getByTestId('submitted-question')).toBeInTheDocument()
+
+    fireEvent.change(textarea, { target: { value: 'New question' } })
+    expect(screen.queryByTestId('submitted-question')).not.toBeInTheDocument()
+  })
+
+  it('does not show submitted question before any submission', () => {
+    render(<QueryInput onSubmit={mockOnSubmit} isLoading={false} />)
+    expect(screen.queryByTestId('submitted-question')).not.toBeInTheDocument()
+  })
+
+  it('does not clear submitted question when typing only whitespace', () => {
+    render(<QueryInput onSubmit={mockOnSubmit} isLoading={false} />)
+    const textarea = screen.getByPlaceholderText('Ask a question about your documents...')
+    const button = screen.getByRole('button', { name: /submit/i })
+
+    fireEvent.change(textarea, { target: { value: 'My question' } })
+    fireEvent.click(button)
+    expect(screen.getByTestId('submitted-question')).toBeInTheDocument()
+
+    fireEvent.change(textarea, { target: { value: '   ' } })
+    expect(screen.getByTestId('submitted-question')).toBeInTheDocument()
+  })
 })