auth.js magic-link login + protected admin shell with bookings list

prisma/migrations/20260501231153_auth/migration.sql

@@ -0,0 +1,11 @@
+-- AlterTable
+ALTER TABLE "User" ADD COLUMN     "image" TEXT;
+
+-- CreateTable
+CREATE TABLE "VerificationToken" (
+    "identifier" TEXT NOT NULL,
+    "token" TEXT NOT NULL,
+    "expires" TIMESTAMPTZ(3) NOT NULL,
+
+    CONSTRAINT "VerificationToken_pkey" PRIMARY KEY ("identifier","token")
+);