Applicatie afmaken en GUI-flow herstellen

Voegt boodschappenlijsten, productbeheer, realtime synchronisatie en browsercache-updates toe. Herstelt login- en sessiegedrag en maakt database-seeding herhaalbaar.\n\nCo-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

config/session.js

@@ -1,8 +1,9 @@
 const session = require("express-session");
 const BetterSqlite3Store = require("better-sqlite3-session-store")(session);
 const Database = require("better-sqlite3");
+const path = require("path");
 
-const db = new Database("sessions.sqlite");
+const db = new Database(path.join(__dirname, "..", "sessions.sqlite"));
 
 module.exports = session({
 
@@ -14,14 +15,17 @@ module.exports = session({
         }
     }),
 
-    secret: process.env.SESSION_SECRET,
+    secret: process.env.SESSION_SECRET || "change-this-development-secret",
 
     resave: false,
 
     saveUninitialized: false,
 
     cookie: {
-        maxAge: 1000 * 60 * 60 * 24 * 30
+        maxAge: 1000 * 60 * 60 * 24 * 30,
+        httpOnly: true,
+        sameSite: "lax",
+        secure: process.env.NODE_ENV === "production"
     }
 
 });