feat: add Analytics page with scan stats API

Charts and JSON export for scan volume; completes core nav surface.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/app/api/analytics/stats/route.ts

@@ -0,0 +1,51 @@
+import { NextResponse } from "next/server";
+import { prisma } from "@/lib/prisma";
+
+export async function GET() {
+  const [total, completed, failed, last7] = await Promise.all([
+    prisma.scan.count(),
+    prisma.scan.count({ where: { status: "COMPLETED" } }),
+    prisma.scan.count({ where: { status: "FAILED" } }),
+    prisma.scan.findMany({
+      where: {
+        createdAt: { gte: new Date(Date.now() - 7 * 24 * 60 * 60 * 1000) },
+      },
+      select: { createdAt: true, status: true },
+      orderBy: { createdAt: "asc" },
+    }),
+  ]);
+
+  const byDay = new Map<string, { scans: number; completed: number }>();
+  for (const row of last7) {
+    const key = row.createdAt.toISOString().slice(0, 10);
+    const cur = byDay.get(key) ?? { scans: 0, completed: 0 };
+    cur.scans += 1;
+    if (row.status === "COMPLETED") cur.completed += 1;
+    byDay.set(key, cur);
+  }
+
+  const daily = [...byDay.entries()].map(([date, v]) => ({
+    date,
+    scans: v.scans,
+    completed: v.completed,
+  }));
+
+  const topDomains = await prisma.scan.groupBy({
+    by: ["domain"],
+    _count: { domain: true },
+    orderBy: { _count: { domain: "desc" } },
+    take: 8,
+  });
+
+  return NextResponse.json({
+    total,
+    completed,
+    failed,
+    successRate: total ? Math.round((completed / total) * 100) : 0,
+    daily,
+    topDomains: topDomains.map((d) => ({
+      domain: d.domain,
+      count: d._count.domain,
+    })),
+  });
+}