Bug Description

When Hermes sends messages to Feishu, markdown source code (including GFM tables |---|) is displayed as raw text instead of being rendered in a card format.

Steps to Reproduce

1. Configure Hermes with Feishu platform enabled
2. Set HERMES_FEISHU_USE_CARD=true in .env
3. Send any message that contains markdown (e.g., tables, headers)

Expected Behavior

• Messages should be rendered as Feishu interactive cards
• GFM markdown tables should be converted to readable ASCII format or properly rendered

Actual Behavior

Raw markdown source code is shown, e.g.:

| Column A | Column B |
|---|---|
| Value 1 | Value 2 |

Environment

• Hermes version: v0.8.0 (2026.4.8)
• Platform: Feishu