feat(core-dsr): Payload impls, recording doubles, DI binders, contract tests

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/core-dsr/src/in-memory-processing-restriction.ts

@@ -0,0 +1,25 @@
+import type { IProcessingRestriction } from "./processing-restriction.interface";
+
+/**
+ * Volatile in-memory IProcessingRestriction. Tracks restriction state in
+ * memory; state is lost on process restart.
+ *
+ * Used in dev-seed and storybook contexts where Payload is unavailable.
+ * Not a recording double — use RecordingProcessingRestriction from
+ * @repo/core-testing for call-assertion in unit tests.
+ */
+export class InMemoryProcessingRestriction implements IProcessingRestriction {
+  private readonly restricted = new Set<string>();
+
+  async setRestriction(subjectId: string, granted: boolean): Promise<void> {
+    if (granted) {
+      this.restricted.add(subjectId);
+    } else {
+      this.restricted.delete(subjectId);
+    }
+  }
+
+  async isRestricted(subjectId: string): Promise<boolean> {
+    return this.restricted.has(subjectId);
+  }
+}