Implement crash-safe streaming worker runtime

crates/remora-object-source/tests/validation.rs

@@ -94,6 +94,21 @@ fn restart_only_identity_cannot_form_checkpoint() {
     );
 }
 
+#[test]
+fn literal_null_version_remains_addressable() {
+    let identity = ObjectSourceIdentity::from_parts(
+        CanonicalUrl::parse("https://objects.example.test").expect("endpoint"),
+        "source-bucket",
+        "key.bin",
+        10,
+        Some("null".into()),
+        None,
+    )
+    .expect("identity");
+    assert_eq!(identity.version_id(), Some("null"));
+    assert!(identity.is_resumable());
+}
+
 #[test]
 fn validation_and_debug_surfaces_hide_keys_and_credentials() {
     let config = ObjectSourceConfig::new(