LearnSpace: full-stack educational whiteboard platform

Node.js/Express backend + vanilla JS frontend.
Features: real-time collaborative whiteboard (SSE), multi-page support,
LaTeX formulas, shapes/connectors, coordinate systems, number lines,
compass, zoom/pan, Catmull-Rom pencil smoothing, ruler/protractor with
rotation & resize controls, minimap navigation overlay, auto-measurements,
multi-page thumbnails sidebar, PNG export, page templates.
Student/teacher workflows: classes, assignments, library, dashboard.
Mobile responsive. SQLite (better-sqlite3).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/utils/audit.js

@@ -0,0 +1,22 @@
+'use strict';
+const db = require('../db/db');
+
+const stmt = db.prepare(
+  "INSERT INTO admin_audit_log (admin_id, action, target, detail, ip) VALUES (?, ?, ?, ?, ?)"
+);
+
+/**
+ * Log an admin action.
+ * @param {object} req - Express request (must have req.user)
+ * @param {string} action - e.g. 'user.role_change', 'user.delete', 'user.ban'
+ * @param {string} [target] - e.g. 'user:42', 'question:15'
+ * @param {string} [detail] - human-readable detail
+ */
+function audit(req, action, target, detail) {
+  try {
+    const ip = req.ip || req.socket?.remoteAddress || '';
+    stmt.run(req.user?.id || 0, action, target || null, detail || null, ip);
+  } catch (e) { console.error('[audit]', e.message); }
+}
+
+module.exports = { audit };