feat: the assistant's answers in Markdown; thinking shows «Думаю…», then «Думал N с», opening smoothly by its arrow

internal/server/web/static/wsutil.js

@@ -58,6 +58,49 @@
     }
     return out;
   }
-  const api = {shellQuote, shellQuoteAll, dropAction, fmtSize, scope, parseActions};
+  // md turns an assistant's text (no ``` blocks - those are drawn apart)
+  // into HTML: headings, lists, quotes, bold, italic, `code` and http(s)
+  // links. Everything is escaped first, so nothing else gets through.
+  const escH = v => String(v).replace(/[&<>"]/g, c => ({'&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;'}[c]));
+  function mdInline(t) {
+    const codes = [];
+    t = t.replace(/`([^`\n]+)`/g, (_, c) => { codes.push(c); return '\u0000' + (codes.length - 1) + '\u0000'; });
+    t = escH(t)
+      .replace(/\*\*([^*\n]+)\*\*/g, '<b>$1</b>')
+      .replace(/(^|[^*\w])\*([^*\n]+)\*(?!\w)/g, '$1<i>$2</i>')
+      .replace(/(^|\W)_([^_\n]+)_(?!\w)/g, '$1<i>$2</i>')
+      .replace(/\[([^\]\n]+)\]\(((?:[^()\s]|\([^()\s]*\))+)\)/g, (_, txt, url) => /^https?:\/\//i.test(url.replace(/&amp;/g, '&'))
+        ? '<a href="' + url + '" target="_blank" rel="noopener">' + txt + '</a>' : txt);
+    return t.replace(/\u0000(\d+)\u0000/g, (_, i) => '<code>' + escH(codes[+i]) + '</code>');
+  }
+  function md(text) {
+    const out = [];
+    let para = [], list = null;
+    const flush = () => {
+      if (para.length) out.push('<p>' + para.map(mdInline).join('<br>') + '</p>');
+      para = [];
+      if (list) { out.push('<' + list.tag + '>' + list.items.map(x => '<li>' + mdInline(x) + '</li>').join('') + '</' + list.tag + '>'); list = null; }
+    };
+    for (const line of String(text).split('\n')) {
+      let m;
+      if (!line.trim()) { flush(); continue; }
+      if ((m = /^#{1,6}\s+(.*)$/.exec(line))) { flush(); out.push('<h4>' + mdInline(m[1]) + '</h4>'); continue; }
+      if (/^\s*(-{3,}|\*{3,})\s*$/.test(line)) { flush(); out.push('<hr>'); continue; }
+      if ((m = /^>\s?(.*)$/.exec(line))) { flush(); out.push('<blockquote>' + mdInline(m[1]) + '</blockquote>'); continue; }
+      const ul = /^\s*[-*•]\s+(.*)$/.exec(line), ol = /^\s*\d+[.)]\s+(.*)$/.exec(line);
+      if (ul || ol) {
+        const tag = ul ? 'ul' : 'ol';
+        if (para.length || (list && list.tag !== tag)) flush();
+        if (!list) list = {tag, items: []};
+        list.items.push((ul || ol)[1]);
+        continue;
+      }
+      if (list) flush();
+      para.push(line);
+    }
+    flush();
+    return out.join('');
+  }
+  const api = {shellQuote, shellQuoteAll, dropAction, fmtSize, scope, parseActions, md};
   if (typeof module !== 'undefined') module.exports = api; else root.WSUtil = api;
 })(this);