fix: Prisma 7 adapter-based connection (no url in schema)

- Use @prisma/adapter-pg for PrismaClient (Prisma 7 removed datasourceUrl/datasources)
- prisma.config.ts: migrate.url for CLI commands
- schema.prisma: no url in datasource (Prisma 7 requirement)

prisma.config.ts

@@ -4,4 +4,9 @@ import { defineConfig } from "prisma/config";
 export default defineConfig({
   earlyAccess: true,
   schema: path.join(__dirname, "prisma", "schema.prisma"),
-});
+  migrate: {
+    async url() {
+      return process.env.DATABASE_URL!;
+    },
+  },
+} as any);