Add server hardware/network detail view with Proxmox sync and agent reporting

Servers & Tasks only tracked scheduled tasks — there was no overview of
the servers themselves and no way to see CPU/RAM/disk/IP info. Add a
clickable server overview (visible to every role, not just admins) that
opens a per-server detail page.

- servers table gains an agent-reported hardware/network snapshot
  (IPs, CPU model/cores/load, memory, disks) and an optional link to a
  Proxmox VM/LXC (integration + node + guest type + vmid).
- Proxmox adapter gains getGuestDetail(): live cores/memory/disk from
  /config, live cpu/mem/uptime from /status/current, and IPs (LXC net
  config directly, QEMU via a best-effort guest-agent call that degrades
  gracefully when the agent isn't installed).
- New GET /api/servers/:id/detail combines whichever hardware source
  applies (live Proxmox vs. last agent report) with a DNS reverse-lookup
  against the DNS module's own record cache, so matching hostnames show
  up next to each IP. New PATCH /api/servers/:id manages the Proxmox
  link.
- agent/linux/report-tasks.sh now also collects and reports IPs,
  CPU/memory/disk info on every check-in (load-average-based CPU number,
  not instantaneous, to keep the agent a cheap oneshot).
- Extracted the per-server task table into a shared ServerTaskTable
  component so the all-servers view and the new detail page render
  tasks identically.

Verified server-side end-to-end against the real dev server (agent
report -> detail endpoint -> DNS match) and the Proxmox adapter against
a mock HTTPS server covering LXC/QEMU config parsing and the
guest-agent-unavailable fallback.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

README.md

@@ -24,7 +24,11 @@ All modules from the original plan are built:
   vars) and their credentials are encrypted at rest
 - **Servers & Tasks** — cron/systemd tracking across Debian/Raspbian servers
   via a lightweight push agent (`agent/linux/`), plus manual entries for
-  things an agent can't see (Docker jobs, backups)
+  things an agent can't see (Docker jobs, backups). A clickable server
+  overview opens a detail page with CPU/RAM/disk status, IP addresses, and
+  matching DNS names (looked up from the DNS module's cache) — live from
+  Proxmox for VM/LXC-backed servers, or from the agent's own hardware
+  report for everything else.
 - **Integrations → Tailscale** — device list with online/authorized status,
   and authorize/deauthorize/remove actions; a live device-count widget.
 - **Integrations → Gitea** — repo list with each repo's last CI run status,