feat: 足迹 Footprints 个人留痕系统

桌面应用(Tauri+React+SQLite)：时间线/记录/学年学科成绩梯度/统计/类型与字段模板/附件内容寻址/详情视图/PWA

同步服务端(sync-server)：多用户+邀请码/LWW推拉/seq游标/附件去重/Docker部署

多端同步地基：uuid v7/HLC混合逻辑时钟/软删除墓碑/sync_oplog，Node与Rust双端一致并通过自动化测试

app/src/hooks/useChart.ts

@@ -0,0 +1,50 @@
+import { useEffect, useRef, useState } from 'react';
+import * as echarts from 'echarts/core';
+import type { EChartsType } from 'echarts/core';
+
+export function useThemeTick() {
+  const [tick, setTick] = useState(0);
+  useEffect(() => {
+    const handler = () => setTick((t) => t + 1);
+    window.addEventListener('fp-theme-change', handler);
+    return () => window.removeEventListener('fp-theme-change', handler);
+  }, []);
+  return tick;
+}
+
+export function inkColor(name: '1' | '2' | '3'): string {
+  return getComputedStyle(document.documentElement).getPropertyValue('--text-' + name).trim() || '#454e5c';
+}
+
+// 图表 hook：回调式 ref —— 容器挂载（含条件渲染后出现）即初始化并立即绘制当前数据；
+// deps 变化时增量更新；容器卸载时销毁实例。
+export function useChart(build: () => echarts.EChartsCoreOption, deps: unknown[]) {
+  const chartRef = useRef<EChartsType | null>(null);
+  const [el, setEl] = useState<HTMLDivElement | null>(null);
+  const buildRef = useRef(build);
+  buildRef.current = build;
+
+  // 挂载/重挂载：初始化实例 + 首次绘制
+  useEffect(() => {
+    if (!el) return;
+    const chart = echarts.init(el);
+    chartRef.current = chart;
+    chart.setOption(buildRef.current(), { notMerge: true });
+    const ro = new ResizeObserver(() => chart.resize());
+    ro.observe(el);
+    return () => {
+      ro.disconnect();
+      chart.dispose();
+      chartRef.current = null;
+    };
+  }, [el]);
+
+  // 数据/主题变化：增量更新
+  useEffect(() => {
+    chartRef.current?.setOption(buildRef.current(), { notMerge: true });
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [el, ...deps]);
+
+  const setRef = (node: HTMLDivElement | null) => setEl(node);
+  return setRef;
+}