fix: 修复任务记录表格高度在不同分辨率下底部被裁剪问题

表格缺少 scroll.y 导致 antd v6 中表体按内容自然撑开，
低分辨率下分页器被推出可视区域。改用 ResizeObserver 动态
监听容器高度并计算 scroll.y，使表头固定、表体内部滚动、
分页器固定底部，适配所有分辨率。

web/frontend/src/pages/DouyuTasksPage.tsx

@@ -252,6 +252,8 @@ export default function DouyuTasksPage({ handbook }: { handbook: HandbookKind })
   const [giftCount, setGiftCount] = useState(() => savedPositiveInteger(DOUYU_GIFT_COUNT_STORAGE_KEY));
   const [selectedGoodsId, setSelectedGoodsId] = useState('');
   const [accountSearch, setAccountSearch] = useState('');
+  const taskRecordAreaRef = useRef<HTMLDivElement | null>(null);
+  const [taskRecordAreaHeight, setTaskRecordAreaHeight] = useState(360);
 
   const [importOpen, setImportOpen] = useState(false);
   const [importPool, setImportPool] = useState<DouyuTaskAccountItem[]>([]);
@@ -383,6 +385,23 @@ export default function DouyuTasksPage({ handbook }: { handbook: HandbookKind })
 
   useEffect(() => { loadData(); }, [loadData]);
 
+  // 监听任务记录区域高度变化，动态计算 scroll.y 实现表体内部滚动
+  useEffect(() => {
+    const node = taskRecordAreaRef.current;
+    if (!node) return;
+    const updateHeight = () => {
+      setTaskRecordAreaHeight(Math.max(200, Math.floor(node.getBoundingClientRect().height)));
+    };
+    updateHeight();
+    if (typeof ResizeObserver === 'undefined') {
+      window.addEventListener('resize', updateHeight);
+      return () => window.removeEventListener('resize', updateHeight);
+    }
+    const observer = new ResizeObserver(updateHeight);
+    observer.observe(node);
+    return () => observer.disconnect();
+  }, []);
+
   useEffect(() => {
     localStorage.setItem(DOUYU_GOLD_AMOUNT_STORAGE_KEY, String(goldAmount));
   }, [goldAmount]);
@@ -1222,20 +1241,22 @@ export default function DouyuTasksPage({ handbook }: { handbook: HandbookKind })
             style={{ flex: 1, minHeight: 0, display: 'flex', flexDirection: 'column', overflow: 'hidden' }}
             styles={{ body: { flex: 1, minHeight: 0, padding: '4px 6px', overflow: 'hidden', display: 'flex', flexDirection: 'column' } }}
           >
-            <Table
-              rowKey="id" size="small" columns={taskColumns} dataSource={visibleTasks}
-              className="douyu-task-record-table"
-              loading={loading}
-              pagination={{
-                pageSize: 15,
-                showSizeChanger: false,
-                size: 'small',
-                showLessItems: true,
-                showTotal: (total) => `共 ${total} 条`,
-              }}
-              tableLayout="fixed"
-              scroll={{ x: 850 }}
-            />
+            <div ref={taskRecordAreaRef} style={{ flex: 1, minHeight: 0, display: 'flex', flexDirection: 'column' }}>
+              <Table
+                rowKey="id" size="small" columns={taskColumns} dataSource={visibleTasks}
+                className="douyu-task-record-table"
+                loading={loading}
+                pagination={{
+                  pageSize: 15,
+                  showSizeChanger: false,
+                  size: 'small',
+                  showLessItems: true,
+                  showTotal: (total) => `共 ${total} 条`,
+                }}
+                tableLayout="fixed"
+                scroll={{ x: 850, y: Math.max(120, taskRecordAreaHeight - 80) }}
+              />
+            </div>
           </Card>
 
           <Card