feat: markdown email support — auto-render + download .md

Worker (send.ts):
- Auto-detect markdown in email body (code blocks, headers, bold, links, lists)
- Convert to styled HTML with dark theme (code blocks, inline code, etc.)
- Only when no explicit HTML is provided

Frontend (Dashboard.tsx):
- Extract text/html from MIME multipart and render it
- Styled code blocks, links, headers, lists in email view
- 📄 Download .md button (exports email as markdown file)
- 📋 Copy text button
- AI agents can now send beautifully formatted emails with code samples

Author: CloudLobster

web/src/pages/Dashboard.tsx

@@ -205,6 +205,29 @@ function extractTextFromMime(raw: string): string {
   return isQP ? decodeQuotedPrintable(body) : body;
 }
 
+function extractHtmlFromMime(raw: string): string | null {
+  if (!raw) return null;
+
+  const boundaryMatch = raw.match(/boundary="?([^"\r\n;]+)"?/);
+  if (!boundaryMatch) return null;
+
+  const boundary = boundaryMatch[1];
+  const parts = raw.split('--' + boundary);
+  for (const part of parts) {
+    if (part.toLowerCase().includes('content-type: text/html')) {
+      const isQP = part.toLowerCase().includes('quoted-printable');
+      const sep = part.includes('\r\n\r\n') ? '\r\n\r\n' : '\n\n';
+      const bodyStart = part.indexOf(sep);
+      if (bodyStart !== -1) {
+        let body = part.slice(bodyStart + sep.length).trim();
+        body = body.replace(/--$/, '').trim();
+        return isQP ? decodeQuotedPrintable(body) : body;
+      }
+    }
+  }
+  return null;
+}
+
 // Clean snippet for inbox list (strip MIME artifacts + decode QP)
 function cleanSnippet(snippet: string | null): string {
   if (!snippet) return '';
@@ -1391,6 +1414,7 @@ function EmailDetail({ auth }: { auth: AuthState }) {
   }
 
   const bodyText = extractTextFromMime(email.body || '');
+  const bodyHtml = extractHtmlFromMime(email.body || '');
 
   return (
     <div>
@@ -1470,8 +1494,51 @@ function EmailDetail({ auth }: { auth: AuthState }) {
             {new Date(email.created_at * 1000).toLocaleString()}
           </div>
         </div>
-        <div className="whitespace-pre-wrap text-gray-300 font-mono text-sm leading-relaxed">
-          {bodyText}
+        {/* Render HTML if available, otherwise plain text */}
+        {bodyHtml ? (
+          <div
+            className="text-gray-300 text-sm leading-relaxed max-w-none
+              [&_pre]:bg-[#1a1a2e] [&_pre]:border [&_pre]:border-gray-700 [&_pre]:rounded-lg [&_pre]:p-4 [&_pre]:overflow-x-auto [&_pre]:text-[13px] [&_pre]:leading-relaxed
+              [&_code]:bg-[#1a1a2e] [&_code]:px-1.5 [&_code]:py-0.5 [&_code]:rounded [&_code]:text-[0.9em] [&_code]:font-mono [&_code]:text-gray-200
+              [&_a]:text-base-blue [&_a]:underline
+              [&_h1]:text-white [&_h2]:text-white [&_h3]:text-white
+              [&_strong]:text-white
+              [&_hr]:border-gray-700
+              [&_ul]:ml-6 [&_ul]:list-disc [&_li]:mb-1
+              [&_p]:mb-3 [&_p]:leading-relaxed"
+            dangerouslySetInnerHTML={{ __html: bodyHtml }}
+          />
+        ) : (
+          <div className="whitespace-pre-wrap text-gray-300 font-mono text-sm leading-relaxed">
+            {bodyText}
+          </div>
+        )}
+
+        {/* Download .md */}
+        <div className="mt-4 pt-4 border-t border-gray-800 flex gap-2">
+          <button
+            onClick={() => {
+              const blob = new Blob([`# ${email.subject || 'Email'}\n\n**From:** ${email.from_addr}\n**To:** ${email.to_addr}\n**Date:** ${new Date(email.created_at * 1000).toISOString()}\n\n---\n\n${bodyText}`], { type: 'text/markdown' });
+              const url = URL.createObjectURL(blob);
+              const a = document.createElement('a');
+              a.href = url;
+              a.download = `${(email.subject || 'email').replace(/[^a-zA-Z0-9]/g, '-').slice(0, 50)}.md`;
+              a.click();
+              URL.revokeObjectURL(url);
+            }}
+            className="text-gray-500 hover:text-gray-300 text-xs flex items-center gap-1 transition"
+          >
+            📄 Download .md
+          </button>
+          <button
+            onClick={() => {
+              navigator.clipboard.writeText(bodyText);
+              alert('Copied to clipboard');
+            }}
+            className="text-gray-500 hover:text-gray-300 text-xs flex items-center gap-1 transition"
+          >
+            📋 Copy text
+          </button>
         </div>
       </div>
     </div>

worker/src/routes/send.ts

@@ -25,6 +25,53 @@ const USDC_NETWORKS: Record<string, { chain: Chain; rpc: string; usdc: string; l
 };
 const USDC_TRANSFER_ABI = parseAbi(['event Transfer(address indexed from, address indexed to, uint256 value)']);
 
+// ── Lightweight Markdown → HTML (zero deps) ──
+function hasMarkdown(text: string): boolean {
+  return /```[\s\S]*?```|^#{1,3} |\*\*.*?\*\*|\[.*?\]\(.*?\)|^- |^\d+\. /m.test(text);
+}
+
+function esc(s: string): string {
+  return s.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;');
+}
+
+function md2html(md: string): string {
+  let html = md
+    // Code blocks (fenced)
+    .replace(/```(\w*)\n([\s\S]*?)```/g, (_, lang, code) =>
+      `<pre style="background:#1a1a2e;border:1px solid #333;border-radius:8px;padding:16px;overflow-x:auto;font-size:13px;line-height:1.5"><code style="color:#e0e0e0;font-family:monospace">${esc(code.trim())}</code></pre>`)
+    // Inline code
+    .replace(/`([^`]+)`/g, '<code style="background:#1a1a2e;padding:2px 6px;border-radius:4px;font-size:0.9em;color:#e0e0e0;font-family:monospace">$1</code>')
+    // Headers
+    .replace(/^### (.+)$/gm, '<h3 style="color:#fff;margin:24px 0 8px">$1</h3>')
+    .replace(/^## (.+)$/gm, '<h2 style="color:#fff;margin:32px 0 12px">$1</h2>')
+    .replace(/^# (.+)$/gm, '<h1 style="color:#fff;margin:32px 0 16px">$1</h1>')
+    // Bold + italic
+    .replace(/\*\*(.+?)\*\*/g, '<strong style="color:#fff">$1</strong>')
+    .replace(/\*(.+?)\*/g, '<em>$1</em>')
+    // Links
+    .replace(/\[([^\]]+)\]\(([^)]+)\)/g, '<a href="$2" style="color:#0052FF" target="_blank">$1</a>')
+    // Horizontal rules
+    .replace(/^---+$/gm, '<hr style="border:none;border-top:1px solid #333;margin:24px 0" />')
+    // Unordered lists
+    .replace(/^- (.+)$/gm, '<li style="margin-bottom:4px">$1</li>')
+    .replace(/(<li[^>]*>.*<\/li>\n?)+/g, m => `<ul style="margin:12px 0;padding-left:24px;color:#ccc">${m}</ul>`)
+    // Ordered lists
+    .replace(/^\d+\. (.+)$/gm, '<li style="margin-bottom:4px">$1</li>');
+
+  // Paragraphs
+  html = html
+    .split('\n\n')
+    .map(block => {
+      block = block.trim();
+      if (!block) return '';
+      if (/^<(h[1-6]|ul|ol|pre|hr|div|table)/.test(block)) return block;
+      return `<p style="margin:12px 0;color:#ccc;line-height:1.6">${block.replace(/\n/g, '<br/>')}</p>`;
+    })
+    .join('\n');
+
+  return `<div style="background:#0a0a0a;color:#e5e5e5;font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,sans-serif;padding:24px;max-width:640px">${html}</div>`;
+}
+
 export const sendRoutes = new Hono<AppBindings>();
 
 sendRoutes.use('/*', authMiddleware());
@@ -252,7 +299,10 @@ sendRoutes.post('/', async (c) => {
 
   // Append signature for free-tier users
   const finalBody = isPro ? enrichedBody : enrichedBody + TEXT_SIGNATURE;
-  const finalHtml = html ? (isPro ? html : html + HTML_SIGNATURE) : undefined;
+  // Auto-generate HTML from markdown if no HTML provided and body contains markdown syntax
+  const autoHtml = (!html && hasMarkdown(enrichedBody)) ? md2html(enrichedBody) : undefined;
+  const rawHtml = html || autoHtml;
+  const finalHtml = rawHtml ? (isPro ? rawHtml : rawHtml + HTML_SIGNATURE) : undefined;
 
   // Build MIME message
   const msg = createMimeMessage();