chore: 初始化仓库

中华文明全图鉴——文物全图系统（PC Web 地图 + NestJS API + 管理后台）。
含三大 IP（文物南迁北归 / 国宝海外回归 / 博物馆手艺人）、AI 文物对话、
文物地图与详情、以及 demo-video-kit 演示视频生成工具。

e2e/add-voice.mjs

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+// 把预生成的解说语音（e2e/voice/clips.json）按字幕出现的真实时间点（narration.json）合成到视频。
+// 因为 run.mjs 已让每步停留足够长，时间点本身不重叠，故直接按时间点放置即可保持声画同步。
+import { execSync } from "child_process";
+import fs from "fs";
+import path from "path";
+import { clean } from "./narration.mjs";
+
+const DIR = path.resolve("e2e/videos");
+const VIDEO_IN = path.join(DIR, "wenwumap-e2e.mp4");
+const VIDEO_OUT = path.join(DIR, "wenwumap-e2e-voiced.mp4");
+
+const sh = (cmd) => execSync(cmd, { stdio: ["ignore", "pipe", "pipe"] }).toString();
+const durationOf = (f) =>
+  parseFloat(sh(`ffprobe -v error -show_entries format=duration -of csv=p=0 "${f}"`).trim());
+
+if (!fs.existsSync(VIDEO_IN)) {
+  console.error("缺少视频：先 node e2e/run.mjs 并转码生成 wenwumap-e2e.mp4");
+  process.exit(1);
+}
+const { narration } = JSON.parse(fs.readFileSync(path.join(DIR, "narration.json"), "utf-8"));
+const clipsMap = JSON.parse(fs.readFileSync(path.resolve("e2e/voice/clips.json"), "utf-8"));
+
+// 按字幕时间点匹配预生成语音
+const clips = [];
+for (const n of narration) {
+  const key = clean(n.text);
+  const c = clipsMap[key];
+  if (!c) {
+    console.warn(`× 缺少语音：${key.slice(0, 24)}…`);
+    continue;
+  }
+  clips.push({ file: path.resolve(c.file), start: n.t, dur: c.dur });
+  console.log(`✓ [${(n.t / 1000).toFixed(1)}s ${c.dur.toFixed(1)}s] ${key.slice(0, 26)}…`);
+}
+if (clips.length === 0) {
+  console.error("无可用解说，请先运行 node e2e/gen-voice.mjs");
+  process.exit(1);
+}
+
+// 视频不够长则冻结末帧补足
+const videoDur = durationOf(VIDEO_IN);
+const audioEnd = Math.max(...clips.map((c) => c.start / 1000 + c.dur)) + 0.6;
+const pad = audioEnd - videoDur;
+
+const inputs = clips.map((c) => `-i "${c.file}"`).join(" ");
+const audioFilters = clips
+  .map((c, i) => `[${i + 1}:a]adelay=${Math.round(c.start)}|${Math.round(c.start)}[a${i}]`)
+  .join(";");
+const mixIn = clips.map((_, i) => `[a${i}]`).join("");
+const amix = `${mixIn}amix=inputs=${clips.length}:normalize=0[a]`;
+
+let videoMap = "0:v";
+let vcodec = "-c:v copy";
+let vfilter = "";
+if (pad > 0.3) {
+  vfilter = `[0:v]tpad=stop_mode=clone:stop_duration=${pad.toFixed(2)}[v];`;
+  videoMap = '"[v]"';
+  vcodec = "-c:v libx264 -pix_fmt yuv420p";
+}
+
+const cmd =
+  `ffmpeg -y -i "${VIDEO_IN}" ${inputs} ` +
+  `-filter_complex "${vfilter}${audioFilters};${amix}" ` +
+  `-map ${videoMap} -map "[a]" ${vcodec} -c:a aac -b:a 160k "${VIDEO_OUT}"`;
+
+console.log(`视频 ${videoDur.toFixed(1)}s / 解说至 ${audioEnd.toFixed(1)}s${pad > 0.3 ? `（末帧补 ${pad.toFixed(1)}s）` : ""}`);
+execSync(cmd, { stdio: "inherit" });
+console.log(`完成：${VIDEO_OUT}`);