Fix __dirname ReferenceError in E2E global setup

The root package.json uses "type": "module" (ESM), so __dirname is
not available. Derive it from import.meta.url instead.

https://claude.ai/code/session_01JJckq16HxKozwoh3XDJcQ1

e2e/global.setup.ts

@@ -6,7 +6,10 @@
  * 2. Seeds the database via the /api/setup endpoint
  */
 import { DockerComposeEnvironment, Wait } from 'testcontainers'
-import { resolve } from 'path'
+import { resolve, dirname } from 'path'
+import { fileURLToPath } from 'url'
+
+const __dirname = dirname(fileURLToPath(import.meta.url))
 
 let environment: Awaited<ReturnType<DockerComposeEnvironment['up']>> | undefined