fix(feishu): render Markdown tables natively instead of falling back to plain text (#61643)

[CAIHEee]

Fixes #61643.

Summary

The Feishu outbound payload builder was force-routing any message containing a Markdown table to the text message type, based on an outdated assumption that post-type md elements do not render tables.

Verified on Feishu IM (PC + mobile, 2026-07-10) that GFM tables now render natively inside md elements — pipe syntax and separator lines render as proper tables with column alignment (left/right/center via :--- / ---: / :---:).

Changes

1. _MARKDOWN_HINT_RE — added (^\|.*\|) so messages containing only a Markdown table still route to post. The existing regex had no clause matching |, which meant table-only messages fell through to plain text.
2. _build_outbound_payload — removed the force-text branch for content matching _MARKDOWN_TABLE_RE. Tables now flow through the standard Markdown rendering path.

Net diff: +9 / −7 lines.

Testing

Stress-tested locally with hermes send --to feishu:

• 2-column simple table → renders correctly
• 4-column table with mixed bold + list + table → renders correctly
• 8-column × 12-row English table → renders with horizontal scroll on mobile (expected)
• 5-column Chinese table → Unicode preserved, no garbled headers
• Long cell content → wraps within cell, doesn't break layout
• Code block containing | → not misidentified as table

Impact

Currently 100% affected: every Feishu message containing a Markdown table displays raw pipe syntax. After this fix, tables render natively.

Environment

• Hermes: latest main
• Feishu client: PC + iOS, 2026-07-10
• Repro: hermes send --to feishu --file <md_with_table.md>

[teknium1]

Thanks for tracing the current plain-text downgrade. Current main still returns text for _MARKDOWN_TABLE_RE matches at plugins/platforms/feishu/adapter.py:4524-4534, so the underlying routing problem remains.

Problems

• The added (^\|.*\|) alternative in _MARKDOWN_HINT_RE is not table-specific: it accepts any line starting and ending with |, without requiring a separator row. It also leaves tables without outer leading pipes unmatched because both it and _MARKDOWN_TABLE_RE require ^|.
• No regression test covers the changed routing. Existing inline-Markdown coverage at tests/gateway/test_feishu.py:2625-2663 only asserts the post path for bold/italic text.

Suggested changes

• Route with a table-specific detector alongside _MARKDOWN_HINT_RE, and support both outer-pipe and no-outer-pipe table forms.
• Add table-only, mixed-content, and non-table pipe-line routing tests.

Automated hermes-sweeper review.

[teknium1]

Closing — this was fixed on main by #68121, which removes the _MARKDOWN_TABLE_RE force-text downgrade and routes tables through post/md, the same direction as this PR. Your live verification on PC + mobile (2026-07-10) was one of the three independent confirmations that made removing the workaround safe to ship. The salvage was based on #58019 (cleanest implementation vs current main, with tests) with #29552 credited as the earliest submitter against the live plugin adapter path; both authors' commits were cherry-picked with authorship preserved. Thanks for contributing a fix for this — it was one of the most-reported bugs in the tracker.