mara's follow-up on the field-alignment fix: narrowing the form panel
left a lot of bare space next to it, and asked for something that
fills it while helping a new user understand what the page does.
Adds a second panel beside the form (stacks under it on a narrow
viewport) explaining the job chain '/api/agents' actually queues:
an authelia identity, then a forge config repo — no container exists
yet after this page, and deploying one onto the chosen hive is a
separate step that isn't wired up server-side.
fc65811d9f