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/fixUtf8.js

@@ -0,0 +1,15 @@
+/**
+ * Multer encodes originalname as latin1 (ISO-8859-1).
+ * Browsers send filenames as UTF-8 bytes, so non-ASCII chars get mangled.
+ * This middleware re-decodes the bytes back to proper UTF-8.
+ */
+function fixUtf8Name(req, _res, next) {
+  if (req.file && req.file.originalname) {
+    try {
+      req.file.originalname = Buffer.from(req.file.originalname, 'latin1').toString('utf8');
+    } catch { /* keep as-is if decoding fails */ }
+  }
+  next();
+}
+
+module.exports = { fixUtf8Name };