Add paginated payment history to user dashboard

Users can now view their own payments (excluding donations) with
server-side pagination (25/page), date range, method, and
payment/refund filters, both on the API and the new client page.

backend/src/controllers/paymentController.js

@@ -349,30 +349,57 @@ const getPayments = async (req, res) => {
   }
 };
 
-// @desc    Get user payments
+// @desc    Get user payments (paginated, excludes donations, supports date range/method/kind filters)
 // @route   GET /api/payments/mypayments
 // @access  Private
 const getUserPayments = async (req, res) => {
   try {
-    // Users should see payments they made (donations) and payments tied to their registrations
-    const payments = await prisma.payment.findMany({
-      where: {
-        OR: [
-          { userId: req.user.id }, // payments made by the user (includes donations)
-          { registration: { userId: req.user.id } } // payments tied to the user's registrations
-        ]
-      },
-      include: {
-        registration: {
-          include: {
-            event: true
-          }
-        },
-        event: true
-      }
-    });
+    const page  = Math.max(1, parseInt(req.query.page)  || 1);
+    const limit = Math.min(25, Math.max(1, parseInt(req.query.limit) || 25));
+    const skip  = (page - 1) * limit;
 
-    res.json(payments);
+    // Users should see payments they made and payments tied to their registrations,
+    // excluding donations.
+    const where = {
+      isDonation: false,
+      OR: [
+        { userId: req.user.id },
+        { registration: { userId: req.user.id } }
+      ]
+    };
+
+    if (req.query.method) {
+      where.method = { startsWith: String(req.query.method), mode: 'insensitive' };
+    }
+
+    if (req.query.kind === 'refund') {
+      where.amount = { lt: 0 };
+    } else if (req.query.kind === 'payment') {
+      where.amount = { gte: 0 };
+    }
+
+    if (req.query.startDate || req.query.endDate) {
+      where.createdAt = {
+        ...(req.query.startDate && { gte: new Date(req.query.startDate) }),
+        ...(req.query.endDate && { lte: new Date(req.query.endDate) })
+      };
+    }
+
+    const [payments, total] = await prisma.$transaction([
+      prisma.payment.findMany({
+        where,
+        include: {
+          registration: { include: { event: true } },
+          event: true
+        },
+        orderBy: { createdAt: 'desc' },
+        skip,
+        take: limit
+      }),
+      prisma.payment.count({ where })
+    ]);
+
+    res.json({ data: payments, total, page, limit, pages: Math.ceil(total / limit) });
   } catch (error) {
     res.status(res.statusCode === 200 ? 400 : res.statusCode).json({ message: safeErrorMessage(error) });
   }