docs(channels): inline Slack manifest into Quick Setup with Recommended/Minimal variants

The Quick Setup steps in docs/channels/slack.md previously sent users to
the `#manifest-and-scope-checklist` anchor lower on the page to copy the
manifest, breaking the copy-paste flow. Pull the manifest inline as a
Mintlify <CodeGroup> for both Socket Mode and HTTP Request URLs tabs and
add a Minimal variant for workspaces that restrict scopes (drops
files:*, reactions:*, pins:*, mpim:*, emoji:read, usergroups:read while
keeping DMs, channel/group history, mentions, App Home, and slash
commands). Recommended matches extensions/slack/src/setup-shared.ts.
Existing Manifest and scope checklist section stays as the canonical
per-scope reference.

Cross-link from docs/concepts/qa-e2e-automation.md so QA maintainers see
the production manifest reference, while keeping the QA Driver/SUT pair
of manifests inline (the lane intentionally needs two distinct apps so
its shape is different from a single-app production install).

docs/concepts/qa-e2e-automation.md

@@ -325,6 +325,8 @@ The lane needs two distinct Slack apps in one workspace, plus a channel both bot
 
 Prefer a Slack workspace dedicated to QA over reusing a production workspace.
 
+The SUT manifest below mirrors the bundled Slack plugin's production install (`extensions/slack/src/setup-shared.ts:10`). For the production-channel setup as users see it, see [Slack channel quick setup](/channels/slack#quick-setup); the QA Driver/SUT pair is intentionally separate because the lane needs two distinct bot user ids in one workspace.
+
 **1. Create the Driver app**
 
 Go to [api.slack.com/apps](https://api.slack.com/apps) → _Create New App_ → _From a manifest_ → pick the QA workspace, paste the following manifest, then _Install to Workspace_: