fix(feishu): render markdown tables as native card elements

[Zeknes]

Feishu's post format with md tags cannot render markdown tables correctly. This fix detects markdown tables and sends them as interactive card elements with Feishu's native table component.

Changes:

• Add _TABLE_RE regex to detect markdown tables in content
• Add _parse_md_table() to parse MD tables into Feishu table elements
• Add _build_card_elements() to split content into markdown + table elements
• Add _split_elements_by_table_limit() for Feishu's 1-table-per-card limit
• Add _build_outbound_payloads() for multi-table content
• Update send() to handle interactive card errors with fallback
• Columns use Feishu message API format (no tag field, with data_type)
• _strip_md_formatting handles links, inline code, bold, italic, strikethrough

[alt-glitch]

Likely duplicate of #12114 (same fix: render markdown tables via Feishu Card native table component). Also related to #19038 and #6003.

[teknium1]

Thanks for tackling a real Feishu rendering limitation. Current main still falls back to text for Markdown tables because post/md can render them blank (plugins/platforms/feishu/adapter.py:4524-4530), so the native-card direction remains relevant.

Problems

• The new plural payload builder can return one card per table, but the new singular wrapper returns only payloads[0]. Current edit_message() calls that singular method once (plugins/platforms/feishu/adapter.py:1958), so a multi-table edit would drop later cards after this is ported.
• The interactive fallback only handles errors matching _POST_CONTENT_INVALID_RE. Related maintainer feedback on fix(feishu): route tables and multi-line code blocks to CardKit 2.0 #19038 required a fallback when a card cannot be sent; this condition does not cover other interactive-card failures. The existing edit fallback is post-only (plugins/platforms/feishu/adapter.py:1963-1971).
• The PR changes no tests despite adding parsing, fan-out, fallback, and chunking behavior.

Suggested changes

• Port to plugins/platforms/feishu/adapter.py, define safe multi-table edit behavior, broaden interactive fallback, and add payload/send/edit tests including escaped-pipe cells and multi-table input.
• Validate the Card JSON payload with a real Feishu bot.

Automated hermes-sweeper review.