fix(feishu): route markdown through Card 2.0 interactive cards (v0.18.2 port)

[Mr8rock]

Summary

Ports the Card 2.0 markdown fix from #45036 to Hermes v0.18.2 via manual port (not cherry-pick) per the sweeper review on #45036 comment 4969941933.

The original PR was opened against the 422-line pre-v0.17.0 gateway/platforms/feishu.py. After release 9de9c25f6 (and the file-move commit referenced by the sweeper) the active adapter is plugins/platforms/feishu/adapter.py (5662 lines in v0.18.2). A cherry-pick of the original commit fails because the source path no longer exists.

What changed (in plugins/platforms/feishu/adapter.py)

• _build_outbound_payload now routes markdown through Feishu Card 2.0 (schema: "2.0", tag: "markdown") — the full CommonMark renderer — instead of the stripped-down tag: "md" post element that silently drops tables, code blocks, lists, headings, italic, strikethrough, and blockquotes.
• Plain prose (no markdown hints) still goes as plain text — no behavior change for non-markdown messages.
• _POST_CONTENT_INVALID_RE extended to detect card-rejection errors ("invalid card content" / "invalid content format").
• 3 fallback sites in the send/edit pipeline now treat both "post" and "interactive" as fallback-eligible (msg_type in ("post", "interactive")).

What was deliberately not changed

Per the sweeper review:

• _build_markdown_post_rows is preserved as-is. It is still live — referenced by _build_post_payload() and _build_media_post_payload() for media captions. The original PR rewrote it, but the sweeper review flagged this as out of scope. No caption regression test was added because no caption behavior changed.
• _build_markdown_post_payload is also untouched; cards are not used for media captions.

Tests

pytest tests/gateway/test_feishu.py → 208 passed on clean v0.18.2 (HEAD 8e734810d).

• 6 assertions in _build_outbound_payload consumers updated to expect msg_type="interactive" and Card 2.0 schema ({"schema": "2.0", "body": {"elements": [{"tag": "markdown", "content": ...}]}}) instead of post rows.
• All _build_post_payload unit tests untouched (the helper still serves media captions).

Why a separate PR (vs. reviving #45036)

#45036's diff targets the old gateway/platforms/feishu.py path, which no longer exists in main. The fix has been a saturated-cluster casualty (tracking issue #27469, canonical partial fix #12114) — opening a fresh PR with a clean rebase on current main and a body that links the original avoids the duplicate-closure risk and gives maintainers a diff that actually applies.

Refs

• fix(feishu): route markdown through Card 2.0 interactive cards #45036 — original fix (Mr8rock, still open)
• [feishu] Unified fix for markdown rendering: inbound escaping + GFM table → Card 2.0 #27469 — saturated cluster tracker
• fix(feishu): render markdown tables via card v2 table component #12114 — canonical "tag:"table"" partial fix

[Mr8rock]

cc @hermes-sweeper

Manual port of #45036 to current main (base c9c9bb33fc, parent of head). Drops the _build_markdown_post_rows rewrite per your earlier note on #45036 — that helper is preserved as-is and still serves media captions via _build_post_payload() / _build_media_post_payload().

What this PR changes:

• _build_outbound_payload routes markdown through Card 2.0 (schema: "2.0", tag: "markdown")
• Plain prose still dispatched as msg_type: text
• _POST_CONTENT_INVALID_RE extended to catch card-rejection errors
• 3 fallback sites treat both "post" and "interactive" as fallback-eligible
• 210 tests passing (tests/gateway/test_feishu.py)

This is a manual port, not a cherry-pick — per your guidance on #45036.

Diff: 2 files, +67 / -44. Branch: Mr8rock:fix/feishu-markdown-card-v2-v0.18.

Will keep an eye on #27469 cluster for any reviewer-consolidation signal.

[alt-glitch]

This was generated by AI during triage.

Related: #68084 already implements the current-path table-only Card 2.0 route. This PR instead sends all detected Markdown through an interactive card, so these are competing scopes rather than duplicates.

[Mr8rock]

Thanks @alt-glitch. Noted — #68121 (post+md path) takes precedence here.

Will leave #68507 open as a Card 2.0 fallback in case #68121 turns up regressions on the markdown table / mixed-content paths. No further pushes from my side; not adding noise to the review queue.

Closing the loop on this thread. Will re-engage if I see regression reports.

[teknium1]

Thanks for the careful current-path port and for preserving the media-caption post builder.

Automated hermes-sweeper review found the user-visible Markdown/table routing issue is already implemented on main through the supported native post/md route rather than Card 2.0:

• plugins/platforms/feishu/adapter.py:4587-4604 routes recognized Markdown, including tables, through post and _build_markdown_post_payload().
• tests/gateway/test_feishu_table_markdown.py:66-125 covers both table-only and mixed prose/table content staying on the Markdown post path with content preserved.
• The implementation landed in a660630986 (fix(feishu): render markdown tables via post+md, not text downgrade) and is in release v2026.7.20 via merged PR fix(feishu): render markdown tables via post+md, remove force-text downgrade #68121.

Closing as implemented on main.