feat(download): 新增历史版本选择，重构下载全链路逻辑与UI

- 重构lib/github-releases.ts：统一预览版判断逻辑，新增支持`vX.Y.Z-N.beta`格式的beta标签，提取复用函数简化代码，将原有重复工具方法抽取至此统一管理并新增平台资产匹配工具
- 新增通用PlatformDownloadGrid多平台下载卡片组件，标准化多平台下载UI实现
- 重构两个下载API接口：统一返回格式并新增历史版本列表数据
- 重构/download和/launcher/join-beta页面：替换使用新的下载组件，新增历史版本选择功能

app/api/beta-version/route.ts

@@ -1,35 +1,29 @@
 import { NextResponse } from "next/server";
+import {
+  fetchReleases,
+  pickBetaRelease,
+  pickAsset,
+  buildDownloadUrl,
+  isBetaRelease,
+  RELEASES_PAGE,
+} from "@/lib/github-releases";
 
 /**
  * 预览版（Beta）发布信息接口
  *
  * 数据源优先级：
- *   1. GitHub Releases API（直连）—— 主源，自动识别最新预览版
- *   2. GitHub Releases API（gh-proxy.com 镜像）—— 国内可达
- *   3. 旧静态源 version.json —— 兜底（同时提供 Beta 协议文本）
+ *   1. GitHub Releases API（直连 -> 镜像）—— 主源，自动识别最新预览版
+ *   2. 旧静态源 version.json —— 兜底（同时提供 Beta 协议 licence 文本）
  *
- * 发布方案与仓库信息见《Electron Windows自动更新方案规划》：
- *   仓库：dream-pep/koring-launcher
- *   预览版 tag：v{base}-beta.{RUN_NUMBER}（如 v1.2.5-beta.16），GitHub 标记为 prerelease
- *   正式版 tag：v{base}-{RUN_NUMBER}（如 v1.2.5-14），非 prerelease
- *   安装包命名：koring-launcher-{version}-setup.exe（electron-builder artifactName）
+ * 返回：
+ *   顶层字段 = 最新预览版（licence 从旧静态源补充，下载需同意协议）
+ *   versions  = 历史预览版列表（新 -> 旧，按资产匹配平台；无 licence 数据，直接下载）
  */
 
-const REPO = "dream-pep/koring-launcher";
-const GITHUB_API = `https://api.github.com/repos/${REPO}/releases?per_page=100`;
-const GITHUB_API_PROXY = `https://gh-proxy.com/https://api.github.com/repos/${REPO}/releases?per_page=100`;
 const LEGACY_URL =
   "https://koring-launcher-file-api.lenjing.cloud/launcher/beta/version.json";
-const RELEASES_PAGE = `https://github.com/${REPO}/releases`;
 
-const GH_HEADERS: Record<string, string> = {
-  "User-Agent": "koring-space-website",
-  Accept: "application/vnd.github+json",
-  "X-GitHub-Api-Version": "2022-11-28",
-};
-
-/** 预览版 tag 形态：v1.2.5-beta.16 */
-const BETA_TAG = /^v?\d+\.\d+\.\d+-beta\.\d+$/i;
+const HISTORY_LIMIT = 10;
 
 const EMPTY_LICENCE = { isNeedAgreat: "false", title: "", text: "", liceURL: "" };
 
@@ -43,94 +37,62 @@ const EMPTY_APPS = {
 const CACHE_TTL = 15 * 60 * 1000;
 const cache = new Map<string, { time: number; value: unknown }>();
 
-async function fetchJson(url: string, headers?: Record<string, string>) {
-  const res = await fetch(url, {
-    headers,
-    cache: "no-store",
-    signal: AbortSignal.timeout(15_000),
-  });
-  if (!res.ok) return null;
-  try {
-    return await res.json();
-  } catch {
-    return null;
-  }
-}
-
-/** 依次尝试多个数据源，返回第一个成功的结果 */
-async function trySources(
-  sources: Array<{ url: string; headers?: Record<string, string> }>
-): Promise<unknown | null> {
-  for (const s of sources) {
-    try {
-      const json = await fetchJson(s.url, s.headers);
-      if (json !== null && json !== undefined) return json;
-    } catch {
-      // 继续尝试下一个源
-    }
-  }
-  return null;
-}
-
-/** 选出最新预览版 release（prerelease 标记或 -beta.N tag） */
-function pickBetaRelease(releases: any[]) {
-  const betas = (releases || []).filter(
-    (r) =>
-      r &&
-      !r.draft &&
-      (r.prerelease === true || BETA_TAG.test(String(r.tag_name || "")))
+function sortDesc(releases: any[]) {
+  return [...(releases || [])].sort((a, b) =>
+    String(b.published_at || b.created_at || "").localeCompare(
+      String(a.published_at || a.created_at || "")
+    )
   );
-  betas.sort((a, b) => {
-    const ta = String(a.published_at || a.created_at || "");
-    const tb = String(b.published_at || b.created_at || "");
-    return tb.localeCompare(ta);
-  });
-  return betas[0] || null;
 }
 
-/** 按文件名匹配 release 资产 */
-function pickAsset(release: any, patterns: RegExp[]) {
-  const assets = release?.assets || [];
-  for (const p of patterns) {
-    const hit = assets.find((a: any) => p.test(String(a?.name || "")));
-    if (hit) return hit;
-  }
-  return null;
-}
-
-function buildPlatforms(release: any, legacyApp: any) {
-  const win = pickAsset(release, [/setup\.exe$/i, /\.exe$/i]);
-  const mac = pickAsset(release, [/\.dmg$/i, /\.zip$/i, /\.pkg$/i]);
-  const lin = pickAsset(release, [
-    /\.appimage$/i,
-    /\.deb$/i,
-    /\.rpm$/i,
-    /\.tar\.gz$/i,
-  ]);
-
+/**
+ * 平台信息（DownlodeURL 为下载直链）
+ * licenceFor：给某平台提供 licence（最新版用旧源协议文本，历史版用空 = 无需同意）
+ */
+function buildPlatforms(release: any, licenceFor: (key: string) => any) {
+  const tag = String(release.tag_name || "");
   const mk = (hit: any, key: string) => ({
     isNoVersion: hit ? "false" : "true",
-    licence: legacyApp?.[key]?.licence ?? EMPTY_LICENCE,
-    DownlodeURL: hit?.browser_download_url || "",
+    licence: licenceFor(key),
+    DownlodeURL: hit ? buildDownloadUrl(tag, hit.name) : "",
   });
 
   return {
-    windows: mk(win, "windows"),
-    macos: mk(mac, "macos"),
-    linux: mk(lin, "linux"),
+    windows: mk(pickAsset(release, [/setup\.exe$/i, /\.exe$/i]), "windows"),
+    macos: mk(pickAsset(release, [/\.dmg$/i, /\.zip$/i, /\.pkg$/i]), "macos"),
+    linux: mk(
+      pickAsset(release, [/\.appimage$/i, /\.deb$/i, /\.rpm$/i, /\.tar\.gz$/i]),
+      "linux"
+    ),
   };
 }
 
-function buildGithubPayload(release: any, legacy: any) {
-  const version = String(release.tag_name || "").replace(/^v/i, "");
+function baseEntry(release: any) {
+  const tag = String(release.tag_name || "");
+  return {
+    version: tag.replace(/^v/i, ""),
+    builddate: release.published_at || release.created_at || "",
+    tag,
+    htmlUrl: release.html_url || `${RELEASES_PAGE}/tag/${tag}`,
+    releaseNotes: release.body || "",
+  };
+}
+
+function buildGithubPayload(beta: any, legacy: any) {
+  // 最新预览版：licence 用旧静态源文本（保持原有"需同意 Beta 协议"体验）
+  const licenceSrc = legacy?.app || null;
   return {
     source: "github",
-    version,
-    builddate: release.published_at || release.created_at || "",
-    tag: release.tag_name,
-    htmlUrl: release.html_url || `${RELEASES_PAGE}/tag/${release.tag_name}`,
-    releaseNotes: release.body || "",
-    app: buildPlatforms(release, legacy?.app),
+    ...baseEntry(beta),
+    app: buildPlatforms(beta, (key) => licenceSrc?.[key]?.licence ?? EMPTY_LICENCE),
+  };
+}
+
+/** 历史预览版条目（无协议要求） */
+function buildHistoryEntry(release: any) {
+  return {
+    ...baseEntry(release),
+    app: buildPlatforms(release, () => EMPTY_LICENCE),
   };
 }
 
@@ -152,20 +114,38 @@ export async function GET() {
   }
 
   // 1) 主源：GitHub Releases API（直连 -> 镜像）
-  const releases = (await trySources([
-    { url: GITHUB_API, headers: GH_HEADERS },
-    { url: GITHUB_API_PROXY, headers: GH_HEADERS },
-  ])) as any[] | null;
+  const releases = await fetchReleases();
 
   // 2) 兜底源：旧静态 JSON（也用于补充 Beta 协议 licence）
-  const legacy = await trySources([{ url: LEGACY_URL }]);
+  let legacy: any = null;
+  try {
+    const res = await fetch(LEGACY_URL, {
+      cache: "no-store",
+      signal: AbortSignal.timeout(15_000),
+    });
+    if (res.ok) legacy = await res.json();
+  } catch {
+    legacy = null;
+  }
 
   let payload: unknown;
 
   if (Array.isArray(releases) && releases.length > 0) {
     const beta = pickBetaRelease(releases);
     if (beta) {
-      payload = buildGithubPayload(beta, legacy);
+      const betaTag = String(beta.tag_name || "");
+      const history = sortDesc(releases)
+        .filter(
+          (r) =>
+            isBetaRelease(r) && String(r.tag_name || "") !== betaTag
+        )
+        .slice(0, HISTORY_LIMIT)
+        .map(buildHistoryEntry);
+
+      payload = {
+        ...buildGithubPayload(beta, legacy),
+        versions: history,
+      };
     } else {
       // GitHub 可达但没有任何预览版
       payload = {
@@ -174,6 +154,7 @@ export async function GET() {
         version: "",
         builddate: "",
         app: EMPTY_APPS,
+        versions: [],
       };
     }
   } else if (legacy) {