Documents user-facing wave-1+2 Slack behavior that had no docs coverage:
- decision table for require_mention / free_response_channels /
require_mention_channels / thread_require_mention / strict_mention /
ignore_other_user_mentions and how they compose
- 'Accepting messages from other bots' section with the post-#69483
semantics: allow_bots=mentions requires a CURRENT mention from
peer bots (text or Block Kit blocks); thread state never admits them
- clarify one-tap buttons (choice buttons + Other free-text mode,
in-place resolution, double-click guard, expiry message)
- slash replies are ephemeral: replace-ack, chunking, 5-post cap with
explicit truncation notice, postEphemeral fallback, never-public rule
- cron deliver targeting (slack -> home channel, slack:C... channel,
slack:U... resolved to DM) incl. standalone sender + MEDIA uploads
- send_message media + bare-user-ID DM resolution and caption behavior
Refs #26184.
6d4f7f4049