docs: clarify requirements

README.md

@@ -4,6 +4,12 @@ REST API for the TrueLayer Software Engineering Challenge. It returns basic Pok
 
 ## Requirements
 
+Install these tools first:
+
+- Rust, via `rustup`, for local development and tests.
+- `make`, for the documented command shortcuts.
+- Docker, for the containerized run path.
+
 You can run it either with Docker or with a local Rust toolchain. Common commands are available through `make`; run `make help` for the full list.
 
 ### Option A: Docker