Build local release artifacts and prepare Compose deployment [skip ci]

.env.example

@@ -1,7 +1,8 @@
-# Copy to .env and adjust. Only ADMIN_PASSWORD really matters.
+# Copy to .env and adjust. If ADMIN_PASSWORD is blank, a random first-start
+# password is printed in `docker compose logs panel`.
 PANEL_PORT=8080
 ADMIN_USERNAME=admin
-ADMIN_PASSWORD=change-me-please
+ADMIN_PASSWORD=
 JWT_SECRET=
 CURSEFORGE_API_KEY=
 MAX_UPLOAD_MB=2048