fix: harden typed metrics review findings

crates/crank-metrics/tests/contract_cli.rs

@@ -0,0 +1,27 @@
+use std::{path::PathBuf, process::Command};
+
+#[test]
+fn contract_check_is_independent_of_current_working_directory() {
+    let directory =
+        std::env::temp_dir().join(format!("crank-metrics-contract-{}", std::process::id()));
+    std::fs::create_dir_all(&directory).unwrap();
+    let output = Command::new(env!("CARGO_BIN_EXE_crank-metrics-contract"))
+        .arg("--check")
+        .current_dir(&directory)
+        .output()
+        .unwrap();
+    std::fs::remove_dir_all(&directory).ok();
+    assert!(
+        output.status.success(),
+        "{}",
+        String::from_utf8_lossy(&output.stderr)
+    );
+    assert!(String::from_utf8_lossy(&output.stdout).contains("metrics_contract_ok"));
+}
+
+#[test]
+fn snapshot_path_is_resolved_from_the_crate_manifest() {
+    let path = PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+        .join("../../docs/schemas/metrics-registry-v1.json");
+    assert!(path.is_file());
+}