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/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[];