add contract hazard declaration, DO collection dates, and booking request currency migrations; implement article body diff component and integrate into contract revision timeline

apps/edr-freight-api/src/modules/contracts/contract-document-diff.util.ts

@@ -4,8 +4,9 @@ import type {
 } from './entities/contract.entity';
 
 /**
- * One recorded change between two document snapshots. Granularity is per
- * article: a body edit is reported as "the body changed", not as a text diff.
+ * One recorded change between two document snapshots. A body edit carries the
+ * text on both sides so the audit trail shows WHAT was rewritten, not merely
+ * that something was — the UI diffs the two strings for display.
  */
 export type ContractDocumentChange =
   | { kind: 'ARTICLE_ADDED'; articleId: string; title: string }
@@ -16,7 +17,14 @@ export type ContractDocumentChange =
       title: string;
       fromTitle: string;
     }
-  | { kind: 'ARTICLE_BODY_CHANGED'; articleId: string; title: string }
+  | {
+      kind: 'ARTICLE_BODY_CHANGED';
+      articleId: string;
+      title: string;
+      /** Body before / after the edit. Absent on revisions recorded earlier. */
+      fromBody?: string;
+      toBody?: string;
+    }
   | {
       kind: 'ARTICLE_REORDERED';
       articleId: string;
@@ -120,6 +128,8 @@ export function diffSnapshots(
         kind: 'ARTICLE_BODY_CHANGED',
         articleId: article.id,
         title: article.title,
+        fromBody: previous.body,
+        toBody: article.body,
       });
     }
     if (previous.order !== article.order) {