mara: the route should reflect creating an agent, and stay separate
from a future agent list page. Renamed AgentsPage -> CreateAgentPage
(file, component, css classes) and moved the route from /agents to
/create-agent - flat, not /agents/new, since index.html's relative
asset links only resolve correctly one path segment deep (filed
separately as a real bug, not fixed here). Leaves the bare /agents
path free for a future roster page.
Adds /agents: a name field that POSTs to swarm-controller's
POST /api/agents (from the CreateIdentity work), shows the queued
job node id, and links to /jobs to watch it settle. Scope matches
the issue exactly - no forge/deploy options, those aren't wired
server-side yet.
