chore: restructure examples into single-file and conf.d-method subdirs

examples/single-file/remotes.yaml  — original monolithic config
examples/conf.d-method/            — one yaml per remote (alpine, github, pypi)

docker-compose updated to mount from examples/single-file/.

docker-compose.yml

@@ -10,7 +10,7 @@ services:
     ports:
       - "8000:8000"
     volumes:
-      - ./examples/remotes.yaml:/app/remotes.yaml:ro,z
+      - ./examples/single-file/remotes.yaml:/app/remotes.yaml:ro,z
       - ./ca-bundle.pem:/app/ca-bundle.pem:ro,z
     environment:
       - CONFIG_PATH=/app/remotes.yaml