fix: repair version detection platform query format

- Fix GetLatestVersionByTypeAndArch to separate platform/architecture
- Query now correctly uses platform='linux' and architecture='amd64'
- Resolves UI showing 'no packages available' despite updates existing

aggregator-web/src/components/AgentUpdatesModal.tsx

@@ -73,6 +73,23 @@ export function AgentUpdatesModal({
       const pkg = packages.find(p => p.id === packageId);
       if (!pkg) throw new Error('Package not found');
 
+      // For single agent updates, use individual update with nonce for security
+      if (selectedAgentIds.length === 1) {
+        const agentId = selectedAgentIds[0];
+
+        // Generate nonce for security
+        const nonceData = await agentApi.generateUpdateNonce(agentId, pkg.version);
+        console.log('[UI] Update nonce generated for single agent:', nonceData);
+
+        // Use individual update endpoint with nonce
+        return agentApi.updateAgent(agentId, {
+          version: pkg.version,
+          platform: pkg.platform,
+          nonce: nonceData.update_nonce
+        });
+      }
+
+      // For multiple agents, use bulk update
       const updateData = {
         agent_ids: selectedAgentIds,
         version: pkg.version,
@@ -82,7 +99,9 @@ export function AgentUpdatesModal({
       return agentApi.updateMultipleAgents(updateData);
     },
     onSuccess: (data) => {
-      toast.success(`Update initiated for ${data.updated?.length || 0} agent(s)`);
+      const count = selectedAgentIds.length;
+      const message = count === 1 ? 'Update initiated for agent' : `Update initiated for ${count} agents`;
+      toast.success(message);
       setIsUpdating(false);
       onAgentsUpdated();
       onClose();

aggregator-web/src/lib/api.ts

@@ -172,6 +172,24 @@ export const agentApi = {
     return response.data;
   },
 
+  // Check if update available for agent
+  checkForUpdateAvailable: async (agentId: string): Promise<{ hasUpdate: boolean; currentVersion: string; latestVersion?: string; reason?: string; platform?: string }> => {
+    const response = await api.get(`/agents/${agentId}/updates/available`);
+    return response.data;
+  },
+
+  // Get update status for agent
+  getUpdateStatus: async (agentId: string): Promise<{ status: string; progress?: number; error?: string }> => {
+    const response = await api.get(`/agents/${agentId}/updates/status`);
+    return response.data;
+  },
+
+  // Generate update nonce for agent (new security feature)
+  generateUpdateNonce: async (agentId: string, targetVersion: string): Promise<{ agent_id: string; target_version: string; update_nonce: string; expires_at: number; expires_in_seconds: number }> => {
+    const response = await api.post(`/agents/${agentId}/update-nonce?target_version=${targetVersion}`);
+    return response.data;
+  },
+
   // Update multiple agents (bulk)
   updateMultipleAgents: async (updateData: {
     agent_ids: string[];