feat(artifacts): add immutable artifact store

scripts/check-rust-boundaries.py

@@ -53,6 +53,8 @@ def package_category(name: str, manifest_path: Path, workspace_root: Path) -> st
         return "metrics"
     if name == "crank-config":
         return "config"
+    if name == "crank-artifacts":
+        return "artifacts"
     if name == "crank-observability":
         return "observability"
     if name == "crank-registry":
@@ -86,13 +88,22 @@ def workspace_packages(metadata: dict[str, Any]) -> dict[str, Package]:
     return packages
 
 
-def dependency_package_ids(raw_package: dict[str, Any], packages_by_name: dict[str, str]) -> list[str]:
+def dependency_package_ids(
+    raw_package: dict[str, Any],
+    packages_by_name: dict[str, str],
+    *,
+    skip_dev: bool = False,
+) -> list[str]:
     dependency_ids: list[str] = []
+    seen: set[str] = set()
     for dependency in raw_package.get("dependencies", []):
+        if skip_dev and dependency.get("kind") == "dev":
+            continue
         dependency_name = dependency["name"]
         dependency_id = packages_by_name.get(dependency_name)
-        if dependency_id is not None:
+        if dependency_id is not None and dependency_id not in seen:
             dependency_ids.append(dependency_id)
+            seen.add(dependency_id)
     return dependency_ids
 
 
@@ -128,6 +139,9 @@ def boundary_reason(source: Package, dependency: Package) -> str | None:
     if source.category == "config":
         return "crank-config must not depend on other workspace crates"
 
+    if source.category == "artifacts":
+        return "crank-artifacts must not depend on other workspace crates"
+
     if source.category == "observability" and dependency.category != "metrics":
         return "crank-observability must not depend on other workspace crates"
 
@@ -161,7 +175,11 @@ def find_violations(metadata: dict[str, Any]) -> list[Violation]:
     for source in sorted(packages.values(), key=lambda package: package.name):
         raw_package = raw_packages_by_id[source.id]
         violations.extend(direct_dependency_violations(raw_package))
-        for dependency_id in dependency_package_ids(raw_package, packages_by_name):
+        for dependency_id in dependency_package_ids(
+            raw_package,
+            packages_by_name,
+            skip_dev=source.category == "artifacts",
+        ):
             dependency = packages[dependency_id]
             reason = boundary_reason(source, dependency)
             if reason is not None: