chore: consolidate new foundation and archive v1 (#1495)

v1/packages/quality-rails/src/evaluator/digest.ts

@@ -0,0 +1,45 @@
+import { createHash } from 'node:crypto';
+
+import type { CheckDefinitionSpec, CheckSetPolicySpec } from './types.js';
+
+// Deterministic JSON: object keys sorted at every level so two specs with the
+// same content always produce the same bytes (and thus the same digest).
+export function canonicalJson(value: unknown): string {
+  if (value === null || typeof value !== 'object') {
+    return JSON.stringify(value);
+  }
+  if (Array.isArray(value)) {
+    return `[${value.map((entry) => canonicalJson(entry)).join(',')}]`;
+  }
+  const record = value as Record<string, unknown>;
+  const keys = Object.keys(record).sort();
+  return `{${keys.map((key) => `${JSON.stringify(key)}:${canonicalJson(record[key])}`).join(',')}}`;
+}
+
+/** sha256 over the canonical JSON of `value`. */
+export function digestContent(value: unknown): string {
+  return createHash('sha256').update(canonicalJson(value), 'utf8').digest('hex');
+}
+
+/**
+ * Content digest of a check definition: covers the declarative spec (id,
+ * version, canonical check, description, applicability, params) — everything a
+ * reviewer reasons about — while excluding the executable function object.
+ * Changing any covered field changes the digest, so a recorded digest always
+ * identifies exactly which definition content produced a verdict.
+ */
+export function digestOfSpec(spec: CheckDefinitionSpec): string {
+  return digestContent({
+    id: spec.id,
+    version: spec.version,
+    canonicalCheck: spec.canonicalCheck,
+    description: spec.description,
+    appliesTo: spec.appliesTo,
+    params: spec.params,
+  });
+}
+
+/** Content digest of the per-subject check-set policy. */
+export function digestOfPolicy(spec: CheckSetPolicySpec): string {
+  return digestContent(spec);
+}