Slack reaction_added events were explicitly acked and dropped, so a user
reacting to a bot message (👍 to approve, ✅ to acknowledge) produced
nothing. Forward them through the normal message pipeline as synthesized
MessageEvents whose text is the reaction emoji (translated to unicode
for common names), keeping the downstream auth gate, thread-context
fetch, dedup, and skill routing unchanged.
- Self-reactions and non-message items are dropped; reactions on
messages not sent by this bot are dropped (Feishu-adapter parity).
- The reacted-to message's thread parent becomes the synthesized
thread_ts so the reaction lands in the same session as a reply would.
- Manifest gains reactions:read scope + reaction_added bot event.
Salvaged from PR #29916 by @bpross.
Related: #33111, #44508, #45265 (same cluster).
Benjamin Ross
9c9b057b73