Index: src/routes/prutter.js
===================================================================
--- src/routes/prutter.js	(revision 7bc636b391c66ac399c33e54f7173a022c6a3cbd)
+++ src/routes/prutter.js	(revision 7bc636b391c66ac399c33e54f7173a022c6a3cbd)
@@ -0,0 +1,137 @@
+/**
+ * Prutter — Direct Messaging routes.
+ *
+ * GET  /prutter                   -> inbox (list of your conversations on THIS site)
+ * GET  /prutter/new?to=<username> -> start (or resume) a conversation, redirects to /prutter/:id
+ * GET  /prutter/:id               -> conversation view (messages + send form)
+ * POST /prutter/:id/send          -> send a message (HTMX-friendly response)
+ *
+ * Scoping: conversations are per-site (PrutterService.getOrCreateConversation
+ * uses res.locals.site.id). Robin's quote: "Prutter = DM (per .com domain)".
+ *
+ * Per-site toggle: site.enable_prutter == 0 -> 404 the whole feature.
+ *
+ * No anonymous DMs — always requires login.
+ */
+
+import express from 'express';
+import db from '../config/database.js';
+import { renderPage } from '../middleware/render.js';
+import { requireAuth } from '../middleware/auth.js';
+import PermissionsService from '../services/PermissionsService.js';
+
+const router = express.Router();
+
+const MAX_MESSAGE_LEN = 2000;
+
+function siteAllowsDM(req, res) {
+  const site = res.locals.site;
+  if (!site) return false;
+  return site.enable_prutter !== 0;
+}
+
+// Middleware: require both auth + Prutter enabled
+function requirePrutter(req, res, next) {
+  if (!siteAllowsDM(req, res)) return res.status(404).send('Prutter not enabled on this site');
+  return requireAuth(req, res, next);
+}
+
+// ==================== INBOX ====================
+router.get('/', requirePrutter, (req, res) => {
+  const prutter = req.app.locals.prutter;
+  const conversations = prutter.getUserConversations(req.session.user.id);
+
+  // Filter to only conversations on THIS site (Prutter scope is per-site)
+  const siteId = res.locals.site.id;
+  const scoped = conversations.filter(c => c.site_id === siteId);
+
+  renderPage(req, res, 'pages/prutter-inbox', {
+    pageTitle: 'Prutter',
+    bodyClass: 'on-special',
+    conversations: scoped,
+  });
+});
+
+// ==================== START / RESUME CONVERSATION ====================
+router.get('/new', requirePrutter, (req, res) => {
+  const targetUsername = (req.query.to || '').toString().trim();
+  if (!targetUsername) {
+    return res.redirect(`${res.locals.siteUrlBase || ''}/prutter`);
+  }
+  const target = db.prepare('SELECT id, username FROM users WHERE username = ?').get(targetUsername);
+  if (!target) return res.status(404).send('User not found');
+  if (target.id === req.session.user.id) {
+    return res.redirect(`${res.locals.siteUrlBase || ''}/prutter`);
+  }
+
+  const prutter = req.app.locals.prutter;
+  const conv = prutter.getOrCreateConversation(req.session.user.id, target.id, res.locals.site.id);
+  res.redirect(`${res.locals.siteUrlBase || ''}/prutter/${conv.id}`);
+});
+
+// ==================== CONVERSATION VIEW ====================
+router.get('/:id', requirePrutter, (req, res) => {
+  const prutter = req.app.locals.prutter;
+  const conv = db.prepare('SELECT * FROM conversations WHERE id = ?').get(req.params.id);
+  if (!conv) return res.status(404).send('Conversation not found');
+
+  // Auth: must be a participant
+  const me = req.session.user.id;
+  if (conv.user_a_id !== me && conv.user_b_id !== me) return res.status(403).send('Not a participant');
+
+  // Scope: this conversation must belong to the resolved site
+  if (conv.site_id !== res.locals.site.id) return res.status(404).send('Conversation not on this site');
+
+  // Other party
+  const otherId = conv.user_a_id === me ? conv.user_b_id : conv.user_a_id;
+  const other = db.prepare('SELECT id, username, avatar_url FROM users WHERE id = ?').get(otherId);
+
+  // Messages (oldest first for natural reading order)
+  const messages = prutter.getMessages(conv.id, 200, 0).reverse();
+
+  // Mark inbound messages as read
+  prutter.markAsRead(conv.id, me);
+
+  renderPage(req, res, 'pages/prutter-conversation', {
+    pageTitle: 'Prutter — ' + (other?.username || ''),
+    bodyClass: 'on-special',
+    conversation: conv,
+    other,
+    messages,
+  });
+});
+
+// ==================== SEND MESSAGE ====================
+router.post('/:id/send', requirePrutter, (req, res) => {
+  const prutter = req.app.locals.prutter;
+  const conv = db.prepare('SELECT * FROM conversations WHERE id = ?').get(req.params.id);
+  if (!conv) return res.status(404).send('Not found');
+
+  const me = req.session.user.id;
+  if (conv.user_a_id !== me && conv.user_b_id !== me) return res.status(403).send('Not a participant');
+  if (conv.site_id !== res.locals.site.id) return res.status(404).send('Wrong site');
+
+  const content = (req.body.content || '').toString().trim();
+  if (!content) return res.status(400).send('Empty');
+  if (content.length > MAX_MESSAGE_LEN) return res.status(413).send('Too long');
+
+  const message = prutter.sendMessage(conv.id, me, content);
+
+  // HTMX request → return the single rendered message HTML, appended to the thread
+  if (req.headers['hx-request']) {
+    return res.send(
+      `<li class="prutter-msg prutter-msg--mine" data-msg-id="${message.id}">` +
+      `<div class="prutter-msg-bubble">${escapeHtml(content)}</div>` +
+      `</li>`
+    );
+  }
+
+  res.redirect(`${res.locals.siteUrlBase || ''}/prutter/${conv.id}`);
+});
+
+function escapeHtml(s) {
+  return s.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;')
+          .replace(/"/g, '&quot;').replace(/'/g, '&#39;');
+}
+
+export default router;