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/storage/mod.rs

@@ -3,7 +3,11 @@ pub mod secure;
 pub mod settings_store;
 pub mod mcp_store;
 
+#[allow(unused_imports)]
 pub use projects_store::*;
+#[allow(unused_imports)]
 pub use secure::*;
+#[allow(unused_imports)]
 pub use settings_store::*;
+#[allow(unused_imports)]
 pub use mcp_store::*;