调整导出 CSV 格式，移除 recordId 和 timestamp，时间单位改为毫秒；优化图表显示逻辑，默认隐藏原始和滤波码值

app/records/[id]/page.tsx

@@ -45,15 +45,14 @@ export default function Page({ params }: { params: Promise<{ id: string }> }) {
   const [error, setError] = useState<string | null>(null)
   const [rec, setRec] = useState<Detail | null>(null)
   // 滤波相关状态
-  const [filterType, setFilterType] = useState<'none' | 'ema' | 'sg' | 'hampel_sg' | 'gauss'>('hampel_sg')
+  const [filterType, setFilterType] = useState<'none' | 'ema' | 'sg' | 'hampel_sg' | 'gauss'>('ema')
   const [emaAlpha, setEmaAlpha] = useState(0.01)
   const [sgWindow, setSgWindow] = useState(21)
   const [sgOrder, setSgOrder] = useState<2 | 3>(3)
   const [hampelWindow, setHampelWindow] = useState(11)
   const [hampelK, setHampelK] = useState(2)
   const [gaussSigma, setGaussSigma] = useState(5)
-  const [showOriginal, setShowOriginal] = useState(false)
-  const [showFiltered, setShowFiltered] = useState(true)
+  // 图例控制显示，不再使用自定义 checkbox；默认隐藏在数据集上配置
 
   useEffect(() => {
     const controller = new AbortController()
@@ -76,10 +75,7 @@ export default function Page({ params }: { params: Promise<{ id: string }> }) {
     return () => controller.abort()
   }, [id])
 
-  // 若存在拟合，默认不显示滤波码值（仅在记录加载时初始化一次）
-  useEffect(() => {
-    if (rec?.fit) setShowFiltered(false)
-  }, [rec?.fit])
+  // 显示策略改由 Chart.js 图例控制，默认隐藏在数据集 hidden 字段中设置
 
   // 侦测小屏（手机）以调整 Chart 布局
   const [isSmall, setIsSmall] = useState(false)
@@ -121,7 +117,8 @@ export default function Page({ params }: { params: Promise<{ id: string }> }) {
 
   const timeAxis = useMemo(() => {
     if (!rec) return [] as number[]
-    const step = rec.sampleCount > 0 ? (rec.duration * 1000) / rec.sampleCount : 0
+    // 使用秒为单位，保留3位小数
+    const step = rec.sampleCount > 0 ? rec.duration / rec.sampleCount : 0
     return Array.from({ length: rec.sampleCount }, (_, i) => +(i * step).toFixed(3))
   }, [rec])
 
@@ -351,15 +348,7 @@ export default function Page({ params }: { params: Promise<{ id: string }> }) {
                     </label>
                   )}
 
-                  <label className="flex items-center gap-2 text-sm">
-                    <input type="checkbox" className="rounded" checked={showFiltered} onChange={(e) => setShowFiltered(e.target.checked)} />
-                    <span>显示滤波码值</span>
-                  </label>
-
-                  <label className="flex items-center gap-2 text-sm">
-                    <input type="checkbox" className="rounded" checked={showOriginal} onChange={(e) => setShowOriginal(e.target.checked)} />
-                    <span>叠加原始</span>
-                  </label>
+                  {/* 由 Chart.js 图例控制数据集显示，不再使用本地 checkbox */}
 
                   <span className="hidden text-xs text-zinc-500 sm:inline">按 Ctrl+滚轮 缩放，拖拽平移</span>
                 </div>
@@ -369,35 +358,29 @@ export default function Page({ params }: { params: Promise<{ id: string }> }) {
                 data={{
                   labels: timeAxis,
                   datasets: [
-                    ...(showOriginal && rec
-                      ? [
-                          {
-                            type: 'line' as const,
-                            label: '原始码值',
-                            data: rec.code,
-                            borderColor: '#a1a1aa',
-                            backgroundColor: 'rgba(161,161,170,0.2)',
-                            borderDash: [4, 4] as any,
-                            borderWidth: 1,
-                            yAxisID: 'yCode',
-                            pointRadius: 0,
-                          },
-                        ]
-                      : []),
-                    ...(showFiltered
-                      ? [
-                          {
-                            type: 'line' as const,
-                            label: '滤波码值',
-                            data: filterType === 'none' ? rec.code : filteredCode,
-                            borderColor: '#0ea5e9',
-                            backgroundColor: 'rgba(14,165,233,0.2)',
-                            borderWidth: 1.5,
-                            yAxisID: 'yCode',
-                            pointRadius: 0,
-                          },
-                        ]
-                      : []),
+                    {
+                      type: 'line' as const,
+                      label: '原始码值',
+                      data: rec.code,
+                      borderColor: '#a1a1aa',
+                      backgroundColor: 'rgba(161,161,170,0.2)',
+                      borderDash: [4, 4] as any,
+                      borderWidth: 1,
+                      yAxisID: 'yCode',
+                      pointRadius: 0,
+                      hidden: true, // 默认不显示原始
+                    },
+                    {
+                      type: 'line' as const,
+                      label: '滤波码值',
+                      data: filterType === 'none' ? rec.code : filteredCode,
+                      borderColor: '#0ea5e9',
+                      backgroundColor: 'rgba(14,165,233,0.2)',
+                      borderWidth: 1.5,
+                      yAxisID: 'yCode',
+                      pointRadius: 0,
+                      hidden: Boolean(rec?.fit), // 存在拟合时默认不显示滤波码值
+                    },
                     ...(rec.fit && forceSeries
                       ? [
                           {
@@ -431,7 +414,7 @@ export default function Page({ params }: { params: Promise<{ id: string }> }) {
                     },
                   },
                   scales: {
-                    x: { title: { display: !isSmall, text: '时间 (ms)' }, ticks: { maxRotation: 0, font: { size: isSmall ? 10 : 12 } } },
+                    x: { title: { display: !isSmall, text: '时间 (s)' }, ticks: { maxRotation: 0, font: { size: isSmall ? 10 : 12 } } },
                     yCode: { type: 'linear' as const, position: 'left' as const, title: { display: !isSmall, text: '码值' }, ticks: { font: { size: isSmall ? 10 : 12 } } },
                     yForce: { type: 'linear' as const, position: 'right' as const, title: { display: !isSmall, text: '力值 (mN)' }, grid: { drawOnChartArea: false }, ticks: { font: { size: isSmall ? 10 : 12 } } },
                   },