Show per-disk usage for Proxmox-linked servers too, not just a total

The agent path showed a per-mount usage table; a Proxmox-linked server
only ever got a single "Disk (allocated)" figure, since that's all the
VM/LXC config alone can tell you -- it's the attached disk's declared
size, not how full it actually is inside the guest. Fix the actual gap
instead of just matching the display: fetch real usage where Proxmox
can see it.

adapter.getGuestDetail() gained a `disks` field (same {mount,
sizeBytes, usedBytes} shape the agent already reports, so the frontend
renders both identically):
- LXC: the host can read straight into the container's root
  filesystem, no agent needed -- status/current's disk/maxdisk fields
  are real usage, not just allocation.
- QEMU: the hypervisor can't see inside a virtual disk at all without
  help, so this calls the QEMU guest agent's get-fsinfo command (same
  "gracefully degrade if the agent's missing/older" tolerance already
  used for its IP-address lookup, and independent of it -- one
  command failing doesn't take out the other). Pseudo-filesystems
  (tmpfs, etc.) are filtered out by checking for a non-empty backing
  `disk` array, the common convention for this endpoint.

Extracted the disks-table JSX (previously only in the agent branch)
into a shared DisksTable component and used it in both branches, and
added a note explaining an empty result when a running QEMU VM's
guest agent doesn't support get-fsinfo (an older agent version).

Verified against a mock Proxmox API over real TLS: an LXC's root
usage, a QEMU VM's real fsinfo mounts (with the disk-less tmpfs entry
correctly filtered), and a QEMU VM whose get-fsinfo fails outright --
confirming that degrades to an empty disks list without throwing and
without affecting the separate network-get-interfaces result.

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

web/src/pages/ServerDetail.tsx

@@ -49,6 +49,28 @@ function usageBar(used: number | null | undefined, total: number | null | undefi
   );
 }
 
+function DisksTable({ disks }: { disks: { mount: string; sizeBytes: number; usedBytes: number }[] }) {
+  if (disks.length === 0) return null;
+  return (
+    <div className="mt-3">
+      <div className="text-secondary small mb-1">Disks</div>
+      <table className="table table-sm table-vcenter mb-0">
+        <tbody>
+          {disks.map((d) => (
+            <tr key={d.mount}>
+              <td>{d.mount}</td>
+              <td>
+                {formatBytes(d.usedBytes)} / {formatBytes(d.sizeBytes)}
+                {usageBar(d.usedBytes, d.sizeBytes)}
+              </td>
+            </tr>
+          ))}
+        </tbody>
+      </table>
+    </div>
+  );
+}
+
 const emptyTaskForm = {
   scheduleType: "docker" as ScheduleType,
   name: "",
@@ -570,11 +592,21 @@ export default function ServerDetail({ user }: { user: CurrentUser }) {
                       <div>{formatUptime(hardware.uptime)}</div>
                     </div>
                   </div>
+                  <DisksTable disks={hardware.disks ?? []} />
                   {hardware.guestAgentAvailable === false && (
                     <div className="text-secondary small mt-3">
                       IP addresses unavailable — the QEMU guest agent isn't installed or running on this VM.
                     </div>
                   )}
+                  {server.proxmoxGuestType === "qemu" &&
+                    hardware.guestAgentAvailable !== false &&
+                    !hardware.disks?.length &&
+                    hardware.status === "running" && (
+                    <div className="text-secondary small mt-3">
+                      Per-disk usage unavailable — the QEMU guest agent doesn't support reporting it (or is still
+                      starting up).
+                    </div>
+                  )}
                 </>
               )}
               {hardware.source === "agent" && (
@@ -601,24 +633,7 @@ export default function ServerDetail({ user }: { user: CurrentUser }) {
                       {usageBar(hardware.memUsedBytes, hardware.memTotalBytes)}
                     </div>
                   </div>
-                  {hardware.disks && hardware.disks.length > 0 && (
-                    <div className="mt-3">
-                      <div className="text-secondary small mb-1">Disks</div>
-                      <table className="table table-sm table-vcenter mb-0">
-                        <tbody>
-                          {hardware.disks.map((d) => (
-                            <tr key={d.mount}>
-                              <td>{d.mount}</td>
-                              <td>
-                                {formatBytes(d.usedBytes)} / {formatBytes(d.sizeBytes)}
-                                {usageBar(d.usedBytes, d.sizeBytes)}
-                              </td>
-                            </tr>
-                          ))}
-                        </tbody>
-                      </table>
-                    </div>
-                  )}
+                  <DisksTable disks={hardware.disks ?? []} />
                 </>
               )}