fix(settings): grey out API & Access while offline

New API Key/delete were already gated on isEffectivelyOnline, but
nothing visually signaled offline state the way Preferences/Profile do
— added the same offline hint banner plus dimmed+disabled the key list
itself, and gated the sheet's own Create button too (in case Offline
Mode gets toggled on while the sheet is already open).

Outpost/Features/Account/SettingsView.swift

@@ -764,6 +764,10 @@ struct SettingsView: View {
 
             Divider().frame(maxWidth: 480)
 
+            if !isEffectivelyOnline {
+                offlineSettingsHint
+            }
+
             HStack {
                 Text("Personal keys")
                     .font(.headline)
@@ -774,6 +778,8 @@ struct SettingsView: View {
             .frame(maxWidth: 480)
 
             apiKeysList
+                .disabled(!isEffectivelyOnline)
+                .opacity(isEffectivelyOnline ? 1 : 0.4)
         }
         .task { await refreshApiKeys() }
         .sheet(isPresented: $isShowingCreateApiKey) {
@@ -908,7 +914,7 @@ struct SettingsView: View {
                 } else {
                     Button("Create") { Task { await createApiKey() } }
                         .buttonStyle(.borderedProminent)
-                        .disabled(newApiKeyName.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty)
+                        .disabled(newApiKeyName.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty || !isEffectivelyOnline)
                 }
             }
         }