/fleet/diagnostics was reachable only by URL: each driver-role row on /fleet now
links to it (FleetDiagnosticsLinks.For escapes the host:port node id). The
diagnostics table showed the string instance id because the wire carries no
display name; the page now joins the authored DriverInstances.Name from the
ConfigDb (enrichment only - a failed lookup falls back to the id) and keeps the
id beneath the name.
Refs #745
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
Joseph Doherty
fc3178cca8