Fix e2e tests for ESM and podman-compose compatibility

Replace __dirname with import.meta.url (required by "type": "module").
Replace --wait flag with manual health polling (unsupported by
podman-compose). Use explicit -p project name to isolate test
containers from dev environment.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/e2e/fixtures.ts

@@ -1,5 +1,8 @@
 import { readFileSync } from 'node:fs'
-import { resolve } from 'node:path'
+import { dirname, resolve } from 'node:path'
+import { fileURLToPath } from 'node:url'
+
+const __dirname = dirname(fileURLToPath(import.meta.url))
 
 interface Fixtures {
   gameId: number