feat: 静态资源与前端 Markdown、浏览量、Gitea 同步内容

- 将 Markdown/KaTeX/高亮/Mermaid 移至 public 与 CDN，减小 Worker 体积
- 文章列表：标题、简介、时间与浏览量；访问文章时递增 view_count
- 新增 migrations/0003 与 blog 路由等配置
- 加入 public 资源与站点图标

Made-with: Cursor

public/js/markdown-client.js

@@ -0,0 +1,96 @@
+import { marked } from "https://esm.sh/marked@15";
+import markedKatex from "https://esm.sh/marked-katex-extension@5?deps=marked@15,katex@0.16";
+import hljs from "https://esm.sh/highlight.js@11";
+import mermaid from "https://cdn.jsdelivr.net/npm/mermaid@10/dist/mermaid.esm.min.mjs";
+
+marked.use(
+  markedKatex({
+    throwOnError: false,
+    nonStandard: true
+  })
+);
+marked.setOptions({ gfm: true, breaks: false });
+
+function decodeHtmlEntities(str) {
+  return String(str)
+    .replace(/ /g, "\u00a0")
+    .replace(/&/g, "&")
+    .replace(/&lt;/g, "<")
+    .replace(/&gt;/g, ">")
+    .replace(/&quot;/g, '"')
+    .replace(/&#39;/g, "'")
+    .replace(/&#(\d+);/g, (_, n) => {
+      const code = Number(n);
+      return code >= 0 && code <= 0x10ffff ? String.fromCharCode(code) : "";
+    })
+    .replace(/&#x([0-9a-fA-F]+);/g, (_, h) => {
+      const code = parseInt(h, 16);
+      return code >= 0 && code <= 0x10ffff ? String.fromCharCode(code) : "";
+    });
+}
+
+function escapeHtml(s) {
+  return String(s)
+    .replace(/&/g, "&amp;")
+    .replace(/</g, "&lt;")
+    .replace(/>/g, "&gt;")
+    .replace(/"/g, "&quot;")
+    .replace(/'/g, "&#39;");
+}
+
+function mermaidFencedToDiv(html) {
+  return html.replace(
+    /<pre><code class="language-mermaid">([\s\S]*?)<\/code><\/pre>/gi,
+    (_, inner) => {
+      const raw = decodeHtmlEntities(inner);
+      return `<div class="mermaid">${escapeHtml(raw)}</div>`;
+    }
+  );
+}
+
+function decodeMdFromB64(b64) {
+  return decodeURIComponent(escape(atob(b64)));
+}
+
+async function renderOne(el) {
+  const b64 = el.getAttribute("data-b64-md");
+  if (!b64) return;
+  let md;
+  try {
+    md = decodeMdFromB64(b64);
+  } catch {
+    el.innerHTML = "<p>正文解码失败。</p>";
+    el.classList.remove("markdown-pending");
+    return;
+  }
+  el.removeAttribute("data-b64-md");
+  let html = marked.parse(md, { async: false });
+  if (typeof html !== "string") html = "";
+  html = mermaidFencedToDiv(html);
+  el.innerHTML = html;
+  el.classList.remove("markdown-pending");
+  el.querySelectorAll("pre code").forEach((block) => {
+    try {
+      hljs.highlightElement(block);
+    } catch {
+      /* ignore unknown languages */
+    }
+  });
+  const mNodes = el.querySelectorAll(".mermaid");
+  if (mNodes.length) {
+    mermaid.initialize({ startOnLoad: false, theme: "neutral" });
+    await mermaid.run({ nodes: mNodes });
+  }
+}
+
+function run() {
+  document.querySelectorAll(".markdown-body[data-b64-md]").forEach((el) => {
+    renderOne(el).catch(() => {
+      el.innerHTML = "<p>渲染失败。</p>";
+      el.classList.remove("markdown-pending");
+    });
+  });
+}
+
+if (document.readyState === "loading") document.addEventListener("DOMContentLoaded", run);
+else run();