feat: update AGENTS.md with installation instructions for Rust components

Author: kosiew

AGENTS.md

@@ -21,6 +21,15 @@
   should omit unnecessary parentheses around `if` conditions.
 - Install the pre-commit hooks with `pre-commit install` and run them with
   `pre-commit run --files <file1> <file2>` or `pre-commit run --all-files`.
+
+Install the required Rust components before running pre-commit:
+
+```bash
+rustup component add rustfmt clippy
+```
+
+If installation is blocked by a proxy, see the [offline installation guide](https://rust-lang.github.io/rustup/installation/other.html).
+
 - The same checks can be run manually using the scripts in `ci/scripts`:
   - `./ci/scripts/python_lint.sh`
   - `./ci/scripts/rust_fmt.sh`