Summary

When Hermes sends a response containing a markdown table to Feishu/Lark, the table rows arrive missing — Feishu's post md and card markdown grammars both silently drop GFM pipe-table syntax, and the same grammars also render <br> tags and ATX headings as literal text. The result is a message where the data the user asked for simply isn't there.

This PR routes any content that contains a GFM table to a card JSON v2 payload whose native table component renders tabular data properly. Each GFM table is parsed and converted to a typed table element (text columns + per-row cells); the surrounding markdown is emitted as markdown elements in the same card.

For non-table markdown, the existing post md path is kept, but with two small fix-ups so the content no longer shows literal junk:

• ATX headings (# foo, ## foo, …) are rewritten as **foo** bold lines (Feishu md does not render any heading levels).
• <br> / <br/> HTML tags are replaced with real newlines (Feishu md does not render HTML line-break tags).

See create_json for the supported post-md grammar.

Before

### Income in the last 7 days
| Date       | Week | Income   |
| ---------- | ---- | ----------: |
| 2026-04-11 | Saturday | $10  |
| 2026-04-12 | Sunday | $11  |

Arrives in Feishu as ### Income in the last 7 days (literal ###, no heading), with the table rows stripped entirely.

After

The same input arrives as a card with:

• a markdown element containing **Income in the last 7 days**
• a native Feishu table (sortable, paginated) with the 3 columns and 2 rows

What's covered

• _split_markdown_for_feishu(content) – parses content into ordered text / table segments.
• _build_feishu_table_element(headers, rows) – emits a card v2 table component (data_type: "text" cells; inline **bold** / `code` / links survive verbatim).
• _build_markdown_card_payload(content) – builds the full card (schema: "2.0", body.elements).
• _transform_text_for_feishu(text) – rewrites headings → bold, <br> → \n.
• _build_outbound_payload – routes to interactive when tables are present, otherwise the existing post / text paths.

Test plan

• pytest tests/gateway/test_feishu.py — 109 passed (no regressions). New cases:
  • test_transform_text_for_feishu_rewrites_headings_and_br
  • test_build_outbound_payload_routes_tables_to_interactive_card
  • test_build_outbound_payload_keeps_non_table_markdown_on_post
  • test_card_splits_text_and_tables_in_order
  • test_card_table_preserves_inline_markdown_in_cells
  • test_send_uses_interactive_card_for_table_markdown
• test_build_post_payload_extracts_title_and_links updated to expect **Title** instead of # Title (the new heading transform).
• Manual verification in a Feishu chat: heading + table + bullets renders as a card with a real table and bold heading (no literal #, no literal <br>, no rows dropped).