Create parent dirs for Ninja file

AGENTS.md

@@ -145,6 +145,10 @@ project:
 - Use `rstest` fixtures for shared setup.
 - Replace duplicated tests with `#[rstest(...)]` parameterised cases.
 - Prefer `mockall` for mocks/stubs.
+- Mock non-deterministic dependencies (e.g., environment variables and the
+  system clock) using dependency injection with the `mockable` crate (traits
+  like `Env` and `Clock`) where appropriate. See
+  `docs/reliable-testing-in-rust-via-dependency-injection.md` for guidance.
 - Prefer `.expect()` over `.unwrap()`.
 - Use `concat!()` to combine long string literals rather than escaping newlines
   with a backslash.

Cargo.toml

@@ -65,8 +65,9 @@ rstest = "0.18.0"
 cucumber = "0.20.0"
 tokio = { version = "1", features = ["macros", "rt-multi-thread"], default-features = false }
 insta = { version = "1", features = ["yaml"] }
-serial_test = "3"
 assert_cmd = "2.0.17"
+mockable = { version = "0.3", features = ["mock"] }
+serial_test = "3"
 
 [[test]]
 name = "cucumber"