fix(feishu): use JSON 2.0 interactive cards for markdown messages (fixes table rendering)

[whutlichao]

Summary

Feishu post-type md elements do not render markdown tables. When table content was detected, the code fell back to msg_type=text (plain text), losing all formatting entirely.

This PR switches markdown content to Feishu interactive cards (msg_type=interactive) using JSON 2.0 structure so the card's "tag": "markdown" element properly renders tables, code blocks, lists, headings, and all other markdown formatting.

Key changes:

• Add _build_markdown_card_payload() — builds JSON 2.0 card with a markdown element
• _build_outbound_payload() — returns interactive type for markdown content (including tables)
• _feishu_send_with_retry() — expanded short-circuit to interactive type
• send() / edit_message() — expanded fallback logic to interactive type

Background

Feishu card markdown elements support tables only in JSON 2.0 structure (with "schema": "2.0" and elements under body.elements). See: https://open.feishu.cn/document/feishu-cards/card-json-v2-components/content-components/rich-text

Testing

All 205 existing Feishu tests pass.

[alt-glitch]

Duplicate of #12114 (canonical, earliest open) — same Feishu markdown-table fix via Card JSON 2.0 / interactive cards. Part of the saturated Feishu table-rendering cluster (#25453, #26429, etc.).

[teknium1]

Thanks for addressing a real Feishu formatting gap: current main still sends detected GFM tables as plain text at plugins/platforms/feishu/adapter.py:4524-4533.

Problems

• The production diff targets gateway/platforms/feishu.py, but that adapter was moved to plugins/platforms/feishu/adapter.py by 5600105478ffde29d7566b45421b100eaa29c4ef; the patch does not apply to current main.
• The changed tests contain no GFM pipe-table input and do not assert a table-capable payload. They only convert existing non-table markdown expectations to interactive.
• _build_outbound_payload() changes all _MARKDOWN_HINT_RE content to interactive cards, while current main keeps non-table markdown on the post path (plugins/platforms/feishu/adapter.py:4531-4532). Canonical duplicate fix(feishu): render markdown tables via card v2 table component #12114 takes the narrower native Card JSON 2.0 table-component route.

Suggested changes

• Port the change to the bundled Feishu plugin and add table-specific payload tests.
• Preserve the post route for non-table markdown and verify the table rendering strategy against the canonical work.

Automated hermes-sweeper review.