feat: 收口文档桥接与 OnlyOffice/Sidebar 回归

- 为 documents.save/meta/content、blocks.patch 与 sidebar.dataset.list 补齐 Rust 协议映射、共享契约与桥接执行器

- 对齐 BlockNote、Mindmap、OnlyOffice 的保存/路由元信息，并补真实浏览器回归脚本与 OnlyOffice 部署基线

- 忽略 Rust 本地构建产物与 Harness 调试状态文件，避免临时产物进入仓库历史

wolai-frontend/src/lib/documents/save-contract.ts

@@ -0,0 +1,48 @@
+import type { Json } from "@/types/supabase";
+
+export type DocumentSavePayload = {
+  documentId: string;
+  workspaceId: string | null;
+  revision: number | null;
+  content: Json;
+  conflictDetectionKey: string | null;
+  snapshotCapturedAt: string | null;
+  blockCount: number | null;
+};
+
+export function buildDocumentSavePayload(input: {
+  documentId: string;
+  workspaceId?: string | null;
+  revision?: number | null;
+  content: Json;
+  conflictDetectionKey?: string | null;
+  snapshotCapturedAt?: string | null;
+  blockCount?: number | null;
+}): DocumentSavePayload {
+  const revision =
+    typeof input.revision === "number" && Number.isInteger(input.revision) && input.revision >= 0
+      ? input.revision
+      : null;
+  const conflictDetectionKey =
+    typeof input.conflictDetectionKey === "string" && input.conflictDetectionKey.trim()
+      ? input.conflictDetectionKey.trim()
+      : null;
+  const snapshotCapturedAt =
+    typeof input.snapshotCapturedAt === "string" && input.snapshotCapturedAt.trim()
+      ? input.snapshotCapturedAt.trim()
+      : null;
+  const blockCount =
+    typeof input.blockCount === "number" && Number.isInteger(input.blockCount) && input.blockCount >= 0
+      ? input.blockCount
+      : null;
+
+  return {
+    documentId: input.documentId.trim(),
+    workspaceId: input.workspaceId?.trim() || null,
+    revision,
+    content: input.content,
+    conflictDetectionKey,
+    snapshotCapturedAt,
+    blockCount,
+  };
+}