da80ac0042
By default `hermes slack manifest` opts the app into Slack's AI Assistant container (assistant_view feature + assistant:write scope + assistant_thread_* events). Slack then renders DMs as the right-hand Assistant split-pane, where every exchange is a thread and bare slash commands (/help, /new, ...) are not delivered as normal command events — they only work when the bot is @mentioned. There was no way to opt out short of hand-editing the generated JSON. Add --no-assistant to emit a flat-DM manifest that omits those three pieces, so DMs render as a normal chat and slash commands dispatch inline. The regular messaging surface (Messages tab, slash commands, Socket Mode, channel + DM scopes/events) is preserved in both modes. Default behaviour is unchanged (assistant mode still on). Tests: cover both manifest modes and the argparse wiring.