fix: ensure userVisible metadata on Goosed session replies

Goosed rejects /sessions/:id/reply when user_message.metadata lacks
userVisible. Normalize metadata before submit and during agent orchestration
so page-generation runs no longer fail before streaming starts.

Co-authored-by: Cursor <cursoragent@cursor.com>

goose-message.test.mjs

@@ -0,0 +1,27 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { ensureGooseUserMessageMetadata } from './goose-message.mjs';
+
+test('ensureGooseUserMessageMetadata adds required visibility flags', () => {
+  const normalized = ensureGooseUserMessageMetadata({
+    role: 'user',
+    content: [{ type: 'text', text: '帮我生成页面' }],
+  });
+  assert.equal(normalized.metadata.userVisible, true);
+  assert.equal(normalized.metadata.agentVisible, true);
+});
+
+test('ensureGooseUserMessageMetadata preserves existing metadata fields', () => {
+  const normalized = ensureGooseUserMessageMetadata({
+    role: 'user',
+    content: [{ type: 'text', text: '编排文本' }],
+    metadata: {
+      displayText: '用户原文',
+      chatIntentRoute: 'agent_orchestration',
+    },
+  });
+  assert.equal(normalized.metadata.displayText, '用户原文');
+  assert.equal(normalized.metadata.chatIntentRoute, 'agent_orchestration');
+  assert.equal(normalized.metadata.userVisible, true);
+  assert.equal(normalized.metadata.agentVisible, true);
+});