feat(练习): 添加 Ctrl+H 快捷键显示答案

- ProcessPracticePage: 按住 Ctrl+H 显示答案，松开隐藏
- ProcessDetailPage: 按住 Ctrl+H 显示答案，松开隐藏
- 解决手在键盘上时不方便点击屏幕查看答案的问题

via [HAPI](https://hapi.run)

Co-Authored-By: HAPI <noreply@hapi.run>

src/pages/ProcessDetailPage.tsx

@@ -177,6 +177,39 @@ export function ProcessDetailPage() {
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [id])
 
+  // Ctrl+H 快捷键显示/隐藏答案
+  useEffect(() => {
+    if (!isPracticeMode) return
+
+    const handleKeyDown = (e: KeyboardEvent) => {
+      if (e.ctrlKey && e.key === 'h') {
+        e.preventDefault()
+        if (!showAnswer) {
+          setShowAnswer(true)
+          setInputLocked(true)
+        }
+      }
+    }
+
+    const handleKeyUp = (e: KeyboardEvent) => {
+      if (e.key === 'Control' || e.key === 'h') {
+        if (showAnswer) {
+          setShowAnswer(false)
+          setInputLocked(false)
+        }
+      }
+    }
+
+    window.addEventListener('keydown', handleKeyDown)
+    window.addEventListener('keyup', handleKeyUp)
+
+    return () => {
+      window.removeEventListener('keydown', handleKeyDown)
+      window.removeEventListener('keyup', handleKeyUp)
+    }
+  }, [isPracticeMode, showAnswer])
+
+
   // ── 验证逻辑 ──────────────────────────────────────────────────────────────
   const validateInput = useCallback(
     (input: string[]) => {

src/pages/ProcessPracticePage.tsx

@@ -319,6 +319,34 @@ export default function ProcessPracticePage() {
     return () => clearTimeout(timer)
   }, [showAnswerForCell, restoreFocus])
 
+  // Ctrl+H 快捷键显示/隐藏答案
+  useEffect(() => {
+    const handleKeyDown = (e: KeyboardEvent) => {
+      if (e.ctrlKey && e.key === 'h') {
+        e.preventDefault()
+        if (currentCellId && !showAnswerForCell) {
+          handleLongPress(currentCellId)
+        }
+      }
+    }
+
+    const handleKeyUp = (e: KeyboardEvent) => {
+      if (e.key === 'Control' || e.key === 'h') {
+        if (showAnswerForCell) {
+          handleLongPressEnd()
+        }
+      }
+    }
+
+    window.addEventListener('keydown', handleKeyDown)
+    window.addEventListener('keyup', handleKeyUp)
+
+    return () => {
+      window.removeEventListener('keydown', handleKeyDown)
+      window.removeEventListener('keyup', handleKeyUp)
+    }
+  }, [currentCellId, showAnswerForCell, handleLongPress, handleLongPressEnd])
+
   // 点击格子切换（允许回顾已答对的格子）
   const handleCellClick = useCallback(
     (cellId: string) => {