Replace phx-click JS.navigate with real <.link navigate> elements
on table rows so users can Ctrl+Click to open in new tabs, use
right-click context menus, and navigate via keyboard. Adds row_link
attr to <.table> core component and applies it to all agent tables.
Converts device list custom table from phx-click to inner links.
Broadcast agent lifecycle events (created/deleted) on a separate
"admin:agents" topic so the admin page updates dynamically when
agents are added or removed from any organization.
Superuser-only page showing all agents across all organizations
and cloud pollers in a single table with live-ticking timestamps
and real-time status updates via PubSub.
