fix: update vulnerable dependencies (flatted, markdownlint-cli2) (#1374)

* fix: update vulnerable dependencies (flatted, markdownlint-cli2)

Co-authored-by: Mossaka <5447827+Mossaka@users.noreply.github.com>

* fix: disable MD060 rule introduced by markdownlint-cli2 upgrade

The markdownlint-cli2 v0.21.0 upgrade introduces the new MD060
(table-column-style) rule which flags 1030 existing table formatting
patterns across the codebase. Disable this rule to match the
project's existing table style conventions.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: Mossaka <5447827+Mossaka@users.noreply.github.com>
Co-authored-by: Jiaxiao (mossaka) Zhou <duibao55328@gmail.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: 3 people

.markdownlint.json

@@ -22,5 +22,6 @@
   "MD041": false,
   "MD047": false,
   "MD056": false,
-  "MD058": false
+  "MD058": false,
+  "MD060": false
 }