PR #2837 added Slack Socket Mode end-to-end ("adapter + guided setup") but
was merged into the `channels` branch, not `main`. As a result the
`setup:auto` Slack flow on main is webhook-only: it always collects a
signing secret and pushes the user toward a public Request URL, with no
Socket Mode option — even though setup/verify.ts already recognizes
SLACK_APP_TOKEN and the channels-branch adapter supports it.
Forward-port the setup-side of #2837 onto current main, re-authored on top
of main's current flow (back-nav, inline agent wiring, operator-role prompt,
welcome DM all preserved):
- setup/channels/slack.ts: add a mode picker (askSlackMode), mode-specific
app-creation steps, collectAppToken() for the xapp- app-level token,
conditional credential collection + env, and a mode-aware post-install
checklist (Socket Mode skips the public-URL guidance).
- setup/add-slack.sh: require/persist either SLACK_APP_TOKEN (Socket Mode)
or SLACK_SIGNING_SECRET (webhook) instead of mandating the signing secret.
Scope is setup-side only: the adapter's socket support already lives on
`channels` (#2837/#2839) and reaches users via /add-slack; the add-slack
SKILL.md doc is handled by #2700.
Rob Stevenson
cf8478ffbb