feat: bump to v0.1.23 with security metrics and UI improvements

- Bump agent and server versions to 0.1.23
- Implement security metrics collection (bound agents, command processing, version compliance)
- Add dismiss button for timed out commands in agent status
- Add config sync endpoint for server->agent configuration updates
- Add ignored updates workflow in AgentUpdatesEnhanced (approve/reject workflow)
- Swap AgentScanners layout (subsystems top, security bottom)
- Replace placeholder security data with database metrics
- Add backpressure detection based on pending command ratios

aggregator-server/internal/api/handlers/agents.go

@@ -1150,7 +1150,7 @@ func (h *AgentHandler) GetAgentConfig(c *gin.Context) {
 	}
 
 	// Verify agent exists
-	agent, err := h.agentQueries.GetAgentByID(agentID)
+	_, err = h.agentQueries.GetAgentByID(agentID)
 	if err != nil {
 		c.JSON(http.StatusNotFound, gin.H{"error": "agent not found"})
 		return