Hide Proxmox Replication tab when no replication signals exist

The Replication tab was gated on `hasPveEstate || replicationChanges.length > 0`,
which meant every PVE estate got an always-visible tab whose only content was
empty-state copy. That broke the pattern set by every other Proxmox sub-tab
(Storage, Backups, Ceph, Mail Gateway), each of which only appears when there
is actual data to show. The `hasPveEstate ||` clause was added in 111af289a
without a recorded rationale; the prior "gate by evidence" design (251e8844d)
correctly gated on `replicationChanges.length > 0` only.

Restore the original gate so Replication matches the rest of the platform
page: it shows up when there is something to show.

frontend-modern/src/features/proxmox/__tests__/proxmoxPageModel.test.ts

@@ -130,7 +130,7 @@ describe('proxmoxPageModel', () => {
     ]);
   });
 
-  it('keeps Replication available for a PVE estate without recent replication events', () => {
+  it('hides Replication for a PVE estate without replication signals', () => {
     const model = buildProxmoxPageModel([
       makeResource({
         id: 'pve-node-1',
@@ -148,10 +148,7 @@ describe('proxmoxPageModel', () => {
       }),
     ]);
 
-    expect(buildVisibleProxmoxTabSpecs(model).map((tab) => tab.id)).toEqual([
-      'overview',
-      'replication',
-    ]);
+    expect(buildVisibleProxmoxTabSpecs(model).map((tab) => tab.id)).toEqual(['overview']);
   });
 
   it('resolves Proxmox suite scope from canonical platform hints', () => {

frontend-modern/src/features/proxmox/proxmoxPageModel.ts

@@ -373,12 +373,11 @@ export function buildProxmoxPageModel(resources: Resource[]): ProxmoxPageModel {
 
 export function buildVisibleProxmoxTabSpecs(model: ProxmoxPageModel): ProxmoxTabSpec[] {
   const visible = new Set<ProxmoxPageTabId>(['overview']);
-  const hasPveEstate = model.pveNodes.length > 0 || model.guests.length > 0;
 
   if (model.storage.length > 0 || model.physicalDisks.length > 0) {
     visible.add('storage');
   }
-  if (hasPveEstate || model.replicationChanges.length > 0) {
+  if (model.replicationChanges.length > 0) {
     visible.add('replication');
   }
   if (model.resources.some(hasBackupSignal) || model.pbs.length > 0) {