Synchronize the work card contract

Why: Consume the Core work result and optional decision snapshot.

Evidence: Generated with make contracts from Core 00f1826.

Impact: Add optional types without changing existing cards.

Refs: feature/workbench-flow-completion

src/contracts.ts

@@ -151,7 +151,20 @@ export interface ActivityCard {
   sourceRunId?: ID; anchorMessageId?: ID;
   kind: CardKind; title: string; status: CardStatus; tone?: string;
   body?: UINode[]; actions?: { id: string; label: string; style?: 'primary' | 'default' | 'danger'; command?: string }[];
-  pinned?: boolean; createdAt: string; updatedAt: string;
+  pinned?: boolean; createdAt: string; updatedAt: string; work?: WorkCard;
+}
+
+export interface WorkCard {
+  result?: string; resultVersion: number; readVersion: number; completedAt?: string;
+  decision?: WorkDecision;
+}
+export interface WorkDecision {
+  mode: 'single' | 'multiple'; state: 'open' | 'deferred' | 'submitted';
+  options?: { id: string; label: string }[];
+  selectedIds?: string[]; freeText?: string; respondedAt?: string;
+}
+export interface WorkCardAction {
+  resultVersion: number; selectedIds?: string[]; freeText?: string;
 }
 
 export interface CardPayload { card: ActivityCard }