Q110: an approval pins the content it approved, and later changes show against it

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/shared/approval-pin.ts

@@ -0,0 +1,15 @@
+/** Exactly what an approved deliverable was when the board approved it. */
+export type ApprovalPin =
+  | { kind: "file"; storagePath: string; sha256: string }
+  | { kind: "document"; documentId: string; version: number };
+
+/** How an approved deliverable stands now against its pin. */
+export type ApprovalDrift = "changed" | "removed";
+
+/** The pin of an approval, or null when it carries none (task approvals keep a task snapshot instead). */
+export function parseApprovalPin(subjectSnapshot: string | null): ApprovalPin | null {
+  if (!subjectSnapshot) return null;
+  const value = JSON.parse(subjectSnapshot) as Partial<ApprovalPin> & { kind?: string };
+  if (value.kind === "file" || value.kind === "document") return value as ApprovalPin;
+  return null;
+}