Fix tiptap selection sync and toolbar event loop

wolai-frontend/src/app/api/documents/content/route.ts

@@ -7,6 +7,8 @@ import {
   buildDocumentQueryEnvelope,
   documentBridgeErrorResponse,
 } from "@/lib/documents/bridge";
+import type { PageSubtreeProjection } from "@/lib/documents/page-subtree";
+import { normalizeDocumentContentResponse } from "@/lib/documents/page-subtree-response";
 import {
   executeRustBridgeQueryTransport,
   resolveRustBridgeQueryPlan,
@@ -35,6 +37,8 @@ export async function GET(request: Request) {
         content?: unknown;
         revision?: number | null;
         conflict_detection_key?: string | null;
+        title?: string | null;
+        page_subtree?: PageSubtreeProjection | null;
       } | null>({
         client,
         plan,
@@ -54,16 +58,17 @@ export async function GET(request: Request) {
         );
       }
 
+      const normalized = normalizeDocumentContentResponse({
+        documentId,
+        title: typeof result.title === "string" && result.title.trim() ? result.title : null,
+        payload: result,
+      });
+
       return NextResponse.json({
-        content: result.content ?? null,
-        revision:
-          typeof result.revision === "number" && Number.isInteger(result.revision)
-            ? result.revision
-            : 0,
-        conflictDetectionKey:
-          typeof result.conflict_detection_key === "string" && result.conflict_detection_key.trim()
-            ? result.conflict_detection_key
-            : `${documentId}:0`,
+        content: normalized.content,
+        revision: normalized.revision,
+        conflictDetectionKey: normalized.conflictDetectionKey,
+        pageSubtree: normalized.pageSubtree,
         meta: {
           requestId: bridgeContext.requestId,
           traceId: bridgeContext.traceId,