feat(desktop): report current user online clients

apps/desktop-client/src/main/runtime-controller.ts

@@ -203,6 +203,7 @@ export interface RuntimeControllerSnapshot {
   lastPullStatus: 'idle' | 'success' | 'failed'
   lastAccountsSyncAt: number
   lastServerTime: string | null
+  onlineClientCount: number | null
   lastError: string | null
 }
 
@@ -251,6 +252,7 @@ interface RuntimeState {
   lastPullStatus: 'idle' | 'success' | 'failed'
   lastAccountsSyncAt: number
   lastServerTime: string | null
+  onlineClientCount: number | null
   lastError: string | null
   activitySeq: number
 }
@@ -280,6 +282,7 @@ const state: RuntimeState = {
   lastPullStatus: 'idle',
   lastAccountsSyncAt: 0,
   lastServerTime: null,
+  onlineClientCount: null,
   lastError: null,
   activitySeq: 0,
 }
@@ -532,6 +535,7 @@ export function getRuntimeControllerSnapshot(): RuntimeControllerSnapshot {
     lastPullStatus: state.lastPullStatus,
     lastAccountsSyncAt: state.lastAccountsSyncAt,
     lastServerTime: state.lastServerTime,
+    onlineClientCount: state.onlineClientCount,
     lastError: state.lastError,
   }
 }
@@ -627,6 +631,7 @@ function clearRuntimeState(): void {
   state.lastPullStatus = 'idle'
   state.lastAccountsSyncAt = 0
   state.lastServerTime = null
+  state.onlineClientCount = null
   state.lastError = null
   state.publishFallbackBackoffUntil = 0
   setSchedulerQueueDepth(localQueueDepth())
@@ -977,6 +982,8 @@ async function sendHeartbeat(source: 'startup' | 'timer'): Promise<void> {
     state.lastHeartbeatAt = Date.now()
     state.lastHeartbeatStatus = 'success'
     state.lastServerTime = response.server_time
+    state.onlineClientCount =
+      response.current_user_online_client_count ?? response.online_client_count ?? null
     state.lastError = null
 
     noteTransportHeartbeat(true)