fix(feishu): route markdown tables through post+tag:md, fix streaming edit fallback

[Zjrua]

Bug

Markdown tables in Feishu messages render as raw pipe-delimited source code instead of being rendered as proper tables. When a table appears in a message, the entire message is downgraded to msg_type: text, stripping all markdown formatting (bold, headings, code blocks, lists) from the same reply.

Related issues: #52786, #52046, #23938, #18704, #9549, #21866, #25452

Root cause

Commit 8e18d1031 (Apr 2026) added _MARKDOWN_TABLE_RE to force msg_type: text for any content containing a markdown table. This was correct at the time — Feishu's post md element did not render tables, and sending table content as post caused blank messages.

However, Feishu's post + tag: md element now renders GFM tables natively. The workaround is obsolete and actively harmful: it downgrades the entire message to plain text, displaying raw | pipe-delimited source code and stripping all other formatting.

Fix

1. Route tables through post (core fix)

Merge the table-detection pattern into _MARKDOWN_HINT_RE so tables are treated like any other markdown content — routed to post + tag: md. Remove the now-unused _MARKDOWN_TABLE_RE and its force-text branch in _build_outbound_payload().

2. Streaming edit fallback (edge case no other PR handles)

During streaming, the first chunk may not yet contain a table (partial content), so it's sent as text. When the full content arrives and edit_message() detects the table, _build_outbound_payload returns post. But Feishu does not allow changing msg_type on message update, so the edit fails and the message stays as raw markdown source.

Added a text -> post fallback in edit_message(): when a text update fails, retry as post with markdown rendering.

Prior work

• Supersedes my earlier PR fix(feishu): route markdown tables through post instead of broken interactive card #45583 (target file path was stale after the plugin migration; included ~100 lines of dead CardKit table-element code that was abandoned in favor of the post approach).
• Related PRs fix: send Feishu markdown tables as post #52790, fix(feishu): stop downgrading messages with tables to plain text #52986, fix(feishu): route markdown tables through post+tag:md instead of force-text #53355 all implement the same core fix (route tables to post). This PR additionally handles the streaming edit edge case.

[tonydwb]

Code Review Summary

Verdict: Approved

Feishu markdown table and heading level fixes are well-scoped and targeted. The changes route tables through the post+tag:md path and normalize heading levels, which are common pain points for Feishu message formatting.

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Reviewed by Hermes Agent

[teknium1]

Thanks for isolating the force-text table workaround; the core routing change is supported by current main, where plugins/platforms/feishu/adapter.py:4524-4534 still returns text before markdown detection for _MARKDOWN_TABLE_RE.

Problems

• plugins/platforms/feishu/adapter.py:1857 in d443e16 only retries when the attempted update is text. The reported stream transition is a previously text message whose final table content is classified as post; that post update bypasses this new branch. Retrying post after the inverse post-to-text failure does not cover the stated case.
• The new fallback test in tests/gateway/test_feishu.py in d443e16 uses plain final content and validates text → post retry, not a final table/post update after an earlier text stream message.

Suggested changes

• Preserve the table-routing change, but rework the stream type-transition behavior around the actual text-origin → post-final case and add a regression test for it.

Automated hermes-sweeper review.

[teknium1]

This guard covers a post-origin message becoming plain text, but the PR description’s failure is the reverse: a text streaming message whose final table is classified as post. That attempted update has msg_type == "post", so this fallback is skipped; please handle or re-scope that actual transition.

[Zjrua]

Closing this PR — the core table-routing change (removing the _MARKDOWN_TABLE_RE force-text downgrade, routing tables through post+tag:md) has already landed on main independently (issue #52786). The _MARKDOWN_HINT_RE now includes the pipe-table pattern natively, and a prefer_post parameter was added to keep chunk consistency on long messages.

The streaming edit fallback (text→post on update rejection) is a separate concern; I'll revisit it if it becomes reproducible on current main.

Thanks for the review feedback!