feat: add License Prisma model + migration

prisma/migrations/20260802123955_add_license/migration.sql

@@ -0,0 +1,16 @@
+-- CreateEnum
+CREATE TYPE "LicenseType" AS ENUM ('perpetual', 'subscription');
+
+-- CreateTable
+CREATE TABLE "licenses" (
+    "id" UUID NOT NULL,
+    "name" TEXT NOT NULL,
+    "vendor" TEXT NOT NULL,
+    "seats_total" INTEGER NOT NULL,
+    "seats_used" INTEGER NOT NULL DEFAULT 0,
+    "expiry_date" DATE,
+    "license_type" "LicenseType" NOT NULL,
+    "created_at" TIMESTAMPTZ(6) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+
+    CONSTRAINT "licenses_pkey" PRIMARY KEY ("id")
+);