feat(db): Add unique index for registration number in users collection

Author: codevoid048

server/controllers/authController.js

@@ -19,15 +19,15 @@ const setAuthCookies = (res, user, token) => {
   res.cookie("jwt", token, {
     httpOnly: true,
     secure: process.env.NODE_ENV === "production",
-    sameSite: process.env.NODE_ENV === "production" ? "None" : "Lax",
+    sameSite: process.env.NODE_ENV === "production" ? "sameSite" : "Lax",
     maxAge: 24 * 60 * 60 * 1000, // 1 day
   });
 
   // Store user ID and email in HTTP-only cookie
   res.cookie("user", JSON.stringify({ id: user._id, email: user.email }), {
     httpOnly: true, // Prevent JavaScript access
     secure: process.env.NODE_ENV === "production",
-    sameSite: process.env.NODE_ENV === "production" ? "None" : "Lax",
+    sameSite: process.env.NODE_ENV === "production" ? "sameSite" : "Lax",
     maxAge: 24 * 60 * 60 * 1000, // 1 day
   });
 };

server/lib/dbIndexes.js

@@ -35,6 +35,7 @@ export const createOptimalIndexes = async () => {
         // Create essential user indexes with explicit names
         await usersCollection.createIndex({ email: 1 }, { unique: true, sparse: true, name: 'email_unique_idx' });
         await usersCollection.createIndex({ username: 1 }, { unique: true, sparse: true, name: 'username_unique_idx' });
+        await usersCollection.createIndex({ registrationNumber: 1 }, { unique: true, sparse: true, name: 'regno_unique_idx' });
         // Skip RegistrationNumber for now - has duplicates
 
         // Performance indexes for leaderboard