Add the V5 server endpoint and UI action to restart coold over SSH with
a fresh host token, plus Flux reconnect handling and coverage for the
new backend, browser, and canvas test suites.
Split V5 dashboard behavior into domain controllers and policies,
add agent token rotation/revocation, status reconciliation jobs,
ingress firewall syncing, and canvas connection APIs.
Add migrations for V5 status tracking, server capabilities, resource
connection aliases, and revoked agent tokens.