fix(web): VitalSignsChart hooks 顺序修复 + 趋势线颜色区分度优化

修复 React hooks 在 early return 之后调用导致的渲染崩溃，
将所有 useMemo 移至条件返回之前。趋势图三系列改用高对比色：
实际值(原色实线)、移动平均(青色短虚线)、趋势线(琥珀色长虚线)。

apps/web/src/pages/health/components/VitalSignsChart.tsx

@@ -214,7 +214,7 @@ export function VitalSignsChart({ patientId, refreshKey }: Props) {
     });
   }, [patientId, refreshKey]);
 
-  // 为每个指标预计算趋势统计
+  // 趋势统计 — 所有 hooks 必须在 early return 之前调用
   const trendStats = useMemo(() => {
     const stats: Record<string, {
       regression: ReturnType<typeof linearRegression>;
@@ -240,6 +240,81 @@ export function VitalSignsChart({ patientId, refreshKey }: Props) {
     return stats;
   }, [metricsData]);
 
+  const selectedMetric = METRICS.find((m) => m.key === selectedKey);
+  const selectedData = selectedKey ? metricsData[selectedKey] : null;
+  const axisLabelStyle = { fill: isDark ? '#94a3b8' : '#475569' };
+
+  const chartSeries = useMemo(() => {
+    if (!selectedKey || !selectedData) return [];
+    const stat = trendStats[selectedKey];
+    if (!stat) return [];
+
+    const points = selectedData.points;
+    const series: { date: string; value: number; series: string; isAnomaly?: boolean }[] = [];
+
+    points.forEach((p, i) => {
+      series.push({
+        date: p.date,
+        value: p.value,
+        series: '实际值',
+        isAnomaly: stat.anomalyIndices.has(i),
+      });
+    });
+
+    stat.ma.forEach((val, i) => {
+      if (val != null) {
+        series.push({
+          date: points[i].date,
+          value: val,
+          series: '移动平均',
+        });
+      }
+    });
+
+    if (stat.regression) {
+      const { intercept, slope } = stat.regression;
+      points.forEach((p, i) => {
+        series.push({
+          date: p.date,
+          value: intercept + slope * i,
+          series: '趋势线',
+        });
+      });
+    }
+
+    return series;
+  }, [selectedKey, selectedData, trendStats]);
+
+  const getTrendDirection = (key: string): 'rising' | 'falling' | 'stable' | null => {
+    const stat = trendStats[key];
+    if (!stat?.regression) return null;
+    const { slope } = stat.regression;
+    if (Math.abs(slope) < 0.01) return 'stable';
+    return slope > 0 ? 'rising' : 'falling';
+  };
+
+  const trendDescription = useMemo(() => {
+    if (!selectedKey || !selectedData || !trendStats[selectedKey]) return null;
+    const stat = trendStats[selectedKey];
+    if (!stat?.regression) return null;
+
+    const { slope, rSquared } = stat.regression;
+    const direction = getTrendDirection(selectedKey);
+    const anomalyCount = stat.anomalyIndices.size;
+    const points = selectedData.points;
+    const totalChange = slope * (points.length - 1);
+
+    return {
+      direction: direction === 'rising' ? '上升' : direction === 'falling' ? '下降' : '平稳',
+      slope,
+      rSquared,
+      totalChange,
+      periodDays: points.length > 1 ? points.length : 0,
+      anomalyCount,
+    };
+  }, [selectedKey, selectedData, trendStats]);
+
+  // Early returns — 放在所有 hooks 之后
   if (loading) {
     return (
       <div style={{ height: 48, display: 'flex', alignItems: 'center', justifyContent: 'center' }}>
@@ -266,87 +341,6 @@ export function VitalSignsChart({ patientId, refreshKey }: Props) {
     );
   }
 
-  const selectedMetric = METRICS.find((m) => m.key === selectedKey);
-  const selectedData = selectedKey ? metricsData[selectedKey] : null;
-  const axisLabelStyle = { fill: isDark ? '#94a3b8' : '#475569' };
-
-  // 为详情图构建多系列数据
-  const chartSeries = useMemo(() => {
-    if (!selectedKey || !selectedData) return [];
-    const stat = trendStats[selectedKey];
-    if (!stat) return [];
-
-    const points = selectedData.points;
-    const series: { date: string; value: number; series: string; isAnomaly?: boolean }[] = [];
-
-    // 原始数据系列
-    points.forEach((p, i) => {
-      series.push({
-        date: p.date,
-        value: p.value,
-        series: '实际值',
-        isAnomaly: stat.anomalyIndices.has(i),
-      });
-    });
-
-    // 移动平均系列
-    stat.ma.forEach((val, i) => {
-      if (val != null) {
-        series.push({
-          date: points[i].date,
-          value: val,
-          series: '移动平均',
-        });
-      }
-    });
-
-    // 趋势线系列（线性回归）
-    if (stat.regression) {
-      const { intercept, slope } = stat.regression;
-      points.forEach((p, i) => {
-        series.push({
-          date: p.date,
-          value: intercept + slope * i,
-          series: '趋势线',
-        });
-      });
-    }
-
-    return series;
-  }, [selectedKey, selectedData, trendStats]);
-
-  // 趋势方向摘要
-  const getTrendDirection = (key: string): 'rising' | 'falling' | 'stable' | null => {
-    const stat = trendStats[key];
-    if (!stat?.regression) return null;
-    const { slope } = stat.regression;
-    if (Math.abs(slope) < 0.01) return 'stable';
-    return slope > 0 ? 'rising' : 'falling';
-  };
-
-  // 趋势描述文本
-  const trendDescription = useMemo(() => {
-    if (!selectedKey || !selectedData || !trendStats[selectedKey]) return null;
-    const stat = trendStats[selectedKey];
-    if (!stat?.regression) return null;
-
-    const { slope, rSquared } = stat.regression;
-    const direction = getTrendDirection(selectedKey);
-    const anomalyCount = stat.anomalyIndices.size;
-    const points = selectedData.points;
-    const periodDays = points.length > 1 ? points.length : 0;
-    const totalChange = slope * (points.length - 1);
-
-    return {
-      direction: direction === 'rising' ? '上升' : direction === 'falling' ? '下降' : '平稳',
-      slope,
-      rSquared,
-      totalChange,
-      periodDays,
-      anomalyCount,
-    };
-  }, [selectedKey, selectedData, trendStats]);
-
   return (
     <div>
       {/* 概览卡片条 */}
@@ -426,17 +420,22 @@ export function VitalSignsChart({ patientId, refreshKey }: Props) {
               y: { title: selectedMetric.unit, label: { style: axisLabelStyle } },
             }}
             style={{
-              lineWidth: 2,
+              lineWidth: (datum: Record<string, unknown>) => {
+                const series = datum.series as string;
+                if (series === '趋势线') return 1.5;
+                if (series === '移动平均') return 2;
+                return 2.5;
+              },
               stroke: (datum: Record<string, unknown>) => {
                 const series = datum.series as string;
-                if (series === '趋势线') return '#94a3b8';
+                if (series === '趋势线') return '#f59e0b';
-                if (series === '移动平均') return selectedMetric.color + '88';
+                if (series === '移动平均') return '#14b8a6';
                 return selectedMetric.color;
               },
               lineDash: (datum: Record<string, unknown>) => {
                 const series = datum.series as string;
-                if (series === '趋势线') return [6, 3];
+                if (series === '趋势线') return [8, 4];
-                if (series === '移动平均') return [];
+                if (series === '移动平均') return [4, 2];
                 return [];
               },
             }}
@@ -463,16 +462,16 @@ export function VitalSignsChart({ patientId, refreshKey }: Props) {
           {/* 图例说明 */}
           <div style={{ display: 'flex', gap: 16, marginTop: 4, justifyContent: 'center' }}>
             <div style={{ display: 'flex', alignItems: 'center', gap: 4 }}>
-              <div style={{ width: 16, height: 2, background: selectedMetric.color }} />
+              <div style={{ width: 16, height: 2.5, background: selectedMetric.color, borderRadius: 1 }} />
               <Text type="secondary" style={{ fontSize: 10 }}>实际值</Text>
             </div>
             <div style={{ display: 'flex', alignItems: 'center', gap: 4 }}>
-              <div style={{ width: 16, borderTop: '2px dashed #94a3b8' }} />
+              <div style={{ width: 16, height: 2, background: '#14b8a6', borderRadius: 1, backgroundRepeat: 'repeat-x', backgroundImage: 'linear-gradient(#14b8a6, #14b8a6)', backgroundSize: '4px 2px', backgroundPosition: '0 0' }} />
-              <Text type="secondary" style={{ fontSize: 10 }}>趋势线</Text>
+              <Text type="secondary" style={{ fontSize: 10 }}>移动平均</Text>
             </div>
             <div style={{ display: 'flex', alignItems: 'center', gap: 4 }}>
-              <div style={{ width: 16, height: 2, background: selectedMetric.color + '88' }} />
+              <div style={{ width: 16, borderTop: '2px dashed #f59e0b' }} />
-              <Text type="secondary" style={{ fontSize: 10 }}>移动平均</Text>
+              <Text type="secondary" style={{ fontSize: 10 }}>趋势线</Text>
             </div>
             <div style={{ display: 'flex', alignItems: 'center', gap: 4 }}>
               <div style={{ width: 8, height: 8, borderRadius: '50%', background: '#ef4444' }} />