fix(mindspace): 修复删除时无法解析 MySQL JSON 导致页面复活

source_snapshot_json 在 mysql2 中已是对象，JSON.parse 失败会使 relative_path 丢失、工作区 HTML 未清理；同步后页面重新出现。

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

mindspace-pages.test.mjs

@@ -2,6 +2,16 @@ import assert from 'node:assert/strict';
 import test from 'node:test';
 import { pageInternals } from './mindspace-pages.mjs';
 
+test('parseJsonColumn accepts mysql json objects and strings', () => {
+  const objectValue = { relative_path: 'public/demo.html', auto_synced: true };
+  assert.deepEqual(pageInternals.parseJsonColumn(objectValue), objectValue);
+  assert.deepEqual(
+    pageInternals.parseJsonColumn(JSON.stringify(objectValue)),
+    objectValue,
+  );
+  assert.deepEqual(pageInternals.parseJsonColumn(null, { ok: true }), { ok: true });
+});
+
 test('normalizePageInput trims values and constrains templates', () => {
   const result = pageInternals.normalizePageInput({
     title: '  页面标题  ',