feat(page-data): add validation suggestions, repair path, and thinking fixes

Map Page Data failure codes to Chinese remediation hints, trigger one-shot
goosed repair for remediable cases, and recover poisoned thinking sessions.
Route local DeepSeek through the no-think proxy via host.docker.internal so
tool rounds no longer hit reasoning_content 400; document gate and case-study
scenarios for event registration repair.

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

mindspace-page-data-finish-guard.test.mjs

@@ -243,6 +243,7 @@ test('buildPageDataCollectRepairPrompt mentions bind and forbids localStorage',
   });
   assert.match(prompt, /private_data_bind_workspace_page/);
   assert.match(prompt, /localStorage/);
+  assert.match(prompt, /纠正建议|FORBIDDEN_LOCAL_STORAGE/);
   assert.match(buildPageDataCollectFailureText(), /page-data-collect/);
 });