fix(feishu): route tables and code blocks to CardKit 2.0 with post/text fallback

[lqhl]

Summary

Routes GFM tables and multi-line fenced code blocks to CardKit 2.0 interactive messages in Feishu, with automatic fallback to plain text when card delivery fails.

Problem

Feishu's post/md tag has two rendering limitations:

1. Tables — GFM table syntax (| col1 | col2 |) is silently dropped
2. Code blocks — Fenced code blocks longer than ~6 lines are truncated

Solution

Three new regex detectors + CardKit 2.0 builder + failure fallback:

• _TABLE_MARKDOWN_RE — detects GFM tables (pipe-separated rows + alignment separator)
• _CODE_BLOCK_RE — detects fenced code blocks with 2+ content lines (short blocks stay in post/md)
• _build_card_payload() — wraps content in a CardKit 2.0 card with tag: markdown element
• _build_outbound_payload() — routes detected content to interactive msg_type

Fallback mechanism (not present in original PR #19038)

If the interactive card send fails (bot lacks card permission, API rejection, etc.), the message automatically falls back to plain text. Three layers of protection:

1. Exception handler in send() — catches send failures, retries as plain text
2. Response check in send() and edit_message() — catches API rejection without exception
3. _feishu_send_with_retry() — interactive failures raise immediately (no retry loop)

Testing

• 11 new unit tests covering table detection, code block detection, CardKit JSON format, regex boundary cases, and mixed content
• 209/209 existing Feishu tests pass (no regressions)
• Live-tested on a real Feishu bot (both tables and code blocks render correctly as CardKit 2.0 cards)

Changes

• gateway/platforms/feishu.py: +62/-3 lines
• tests/gateway/test_feishu.py: +114/-0 lines

Related

• Closes [Feishu] Code blocks cannot be expanded — only first ~2 lines visible #19035 (code block truncation)
• Closes [Feishu] Markdown tables not rendering in Feishu messages #9549 (table rendering)
• Based on / supersedes fix(feishu): route tables and multi-line code blocks to CardKit 2.0 #19038 (adds fallback + live testing)
• Related: [Feishu Bug] Markdown source code displayed instead of rendered card format #7022, fix(feishu): markdown tables not rendering as interactive cards — simplify _should_send_as_card() trigger condition #9536, ## Problem When sending markdown table syntax (| col1 | col2 |) in Feishu, the message displays as plain text instead of being rendered as a table. This works correctly in OpenClaw. ## Environment - Hermes Agent version: [latest] - Feishu integration via WebSocket - Using native markdown table syntax in messages ## Expected behavior Markdown tables should render as formatted Feishu table messages, similar to how OpenClaw handles them. ## Screenshots [Attach screenshot comparing OpenClaw vs Hermes Agent rendering] ## Additional context The Feishu platform adapter uses post msg_type with markdown, but the markdown hint regex may not be detecting table syntax properly. #7310

[lqhl]

I've tested this PR with my feishu bot:

[liuhao1024]

Minor: Comment/regex mismatch in _CODE_BLOCK_RE

The inline comment says "route 3+ content lines to CardKit 2.0" but the regex uses {2,} which matches 2+ content lines:

# Multi-line fenced code block (opening fence + 2+ content lines + closing fence)
# Empty or 1-line blocks render fine in post/md; route 3+ content lines to CardKit 2.0.
_CODE_BLOCK_RE = re.compile(r"^```[^\n]*\n(.*\n){2,}```", re.MULTILINE | re.DOTALL)

The test at line 217 confirms a 2-line block ("```\na\nb\n```") does match, so the regex behavior is {2,}. Either:

• Change {2,} → {3,} if the intent is truly 3+ content lines, or
• Update the comment to say "2+ content lines"

Additionally, re.DOTALL is unnecessary here since \n is already explicit in the pattern. It makes .* match across newlines which adds backtracking complexity without changing the outcome on well-formed input. Consider dropping it.

[lqhl]

@liuhao1024 Thanks for catching this! Fixed in 8a60abe:

1. Comment updated: "3+ content lines" → "2+ content lines" to match the {2,} regex
2. Removed re.DOTALL — as you noted, \n is already explicit so DOTALL only adds backtracking overhead

Both changes are comment/cosmetic — the regex behavior is unchanged, 209/209 feishu tests still pass.

[lqhl]

@teknium1 hi, can you take a look?

[teknium1]

Thanks for the Feishu rendering work. The table issue is still present on current main: plugins/platforms/feishu/adapter.py:4524-4534 detects GFM tables and intentionally sends them as plain text.

Problems

• The PR changes gateway/platforms/feishu.py, but the live adapter was relocated to plugins/platforms/feishu/adapter.py by 560010547; GitHub now reports this branch as conflicting.
• Current main already handles fenced blocks by splitting them into dedicated post rows (plugins/platforms/feishu/adapter.py:577-623, covered from tests/gateway/test_feishu.py:2666). The CardKit requirement for that path should be re-established against the current implementation.

Suggested changes

• Port the table/card routing and fallback behavior to the plugin adapter, and update tests to import plugins.platforms.feishu.adapter.
• Keep focused table and fallback coverage; revalidate the code-block cases against the current row-splitting behavior.

This is an automated hermes-sweeper review.

[teknium1]

This adapter path was relocated to plugins/platforms/feishu/adapter.py by 560010547; current main has no gateway/platforms/feishu.py. Please port this change and its tests to the plugin adapter rather than resolving the conflict against the deleted path.