Clean up compiler warnings and document Ollama/LiteLLM backends

Remove unused `any_docker_mcp()` function, add `#[allow(unused_imports)]`
and `#[allow(dead_code)]` annotations to suppress false-positive warnings.
Update README.md and HOW-TO-USE.md with Ollama and LiteLLM auth backend
documentation including best-effort compatibility notices.

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

app/src-tauri/src/docker/network.rs

@@ -48,6 +48,7 @@ pub async fn ensure_project_network(project_id: &str) -> Result<String, String>
 }
 
 /// Connect a container to the project network.
+#[allow(dead_code)]
 pub async fn connect_container_to_network(
     container_id: &str,
     network_name: &str,