Fix frontend layout and update backend dependencies

- Add #app flex container CSS so the app fills the full viewport height
- Bump bcryptjs, express, multer, sqlite3 to latest versions

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

gpx-vis-backend/package.json

@@ -9,19 +9,23 @@
     "test": "mocha --require test/setup.js 'test/**/*.test.js' --timeout 10000"
   },
   "dependencies": {
-    "bcryptjs": "^2.4.3",
+    "bcryptjs": "^3.0.3",
     "compression": "^1.7.4",
     "cors": "^2.8.5",
-    "express": "^4.18.2",
+    "express": "^5.2.1",
     "jsonwebtoken": "^9.0.2",
-    "multer": "^1.4.5-lts.1",
+    "multer": "^2.1.1",
     "mysql2": "^3.7.1",
     "sequelize": "^6.35.2",
-    "sqlite3": "^5.1.7",
+    "sqlite3": "^6.0.1",
     "xml2js": "^0.6.2"
   },
   "devDependencies": {
     "mocha": "^11.7.5",
     "supertest": "^7.2.2"
+  },
+  "overrides": {
+    "diff": "^8.0.3",
+    "serialize-javascript": "^7.0.4"
   }
 }

gpx-vis-frontend/css/style.css

@@ -240,6 +240,13 @@ form button[type="submit"]:hover {
   padding: 4px 10px;
 }
 
+/* ===== App Container ===== */
+#app {
+  flex: 1;
+  flex-direction: column;
+  overflow: hidden;
+}
+
 /* ===== Main Content ===== */
 #main-content {
   display: flex;