feat: add CPU usage to agent response and compact cards

Backend:
- Add cpuUsage field to AgentInstanceResponse (-1 if unavailable)
- Add queryAgentCpuUsage() to AgentRegistrationController — queries
  avg CPU per instance from agent_metrics over last 2 minutes
- Wire CPU into agent list response via withCpuUsage()

Frontend:
- Add cpuUsage to schema.d.ts
- Compute maxCpu per AppGroup (max across all instances)
- Show "X% cpu" on compact cards when available (hidden when -1)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cameleer-server-app/src/main/java/com/cameleer/server/app/controller/AgentRegistrationController.java

@@ -329,6 +329,7 @@ public class AgentRegistrationController {
 
         // Enrich with runtime metrics from continuous aggregates
         Map<String, double[]> agentMetrics = queryAgentMetrics();
+        Map<String, Double> cpuByInstance = queryAgentCpuUsage();
         final List<AgentInfo> finalAgents = agents;
 
         List<AgentInstanceResponse> response = finalAgents.stream()
@@ -341,7 +342,11 @@ public class AgentRegistrationController {
                         double agentTps = appAgentCount > 0 ? m[0] / appAgentCount : 0;
                         double errorRate = m[1];
                         int activeRoutes = (int) m[2];
-                        return dto.withMetrics(agentTps, errorRate, activeRoutes);
+                        dto = dto.withMetrics(agentTps, errorRate, activeRoutes);
+                    }
+                    Double cpu = cpuByInstance.get(a.instanceId());
+                    if (cpu != null) {
+                        dto = dto.withCpuUsage(cpu);
                     }
                     return dto;
                 })
@@ -377,6 +382,27 @@ public class AgentRegistrationController {
         return result;
     }
 
+    /** Query average CPU usage per agent instance over the last 2 minutes. */
+    private Map<String, Double> queryAgentCpuUsage() {
+        Map<String, Double> result = new HashMap<>();
+        Instant now = Instant.now();
+        Instant from2m = now.minus(2, ChronoUnit.MINUTES);
+        try {
+            jdbc.query(
+                    "SELECT instance_id, avg(metric_value) AS cpu_avg " +
+                            "FROM agent_metrics " +
+                            "WHERE metric_name = 'process.cpu.usage.value'" +
+                            " AND collected_at >= " + lit(from2m) + " AND collected_at < " + lit(now) +
+                            " GROUP BY instance_id",
+                    rs -> {
+                        result.put(rs.getString("instance_id"), rs.getDouble("cpu_avg"));
+                    });
+        } catch (Exception e) {
+            log.debug("Could not query agent CPU usage: {}", e.getMessage());
+        }
+        return result;
+    }
+
     /** Format an Instant as a ClickHouse DateTime literal. */
     private static String lit(Instant instant) {
         return "'" + java.time.format.DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")

cameleer-server-app/src/main/java/com/cameleer/server/app/dto/AgentInstanceResponse.java

@@ -25,7 +25,8 @@ public record AgentInstanceResponse(
         double errorRate,
         int activeRoutes,
         int totalRoutes,
-        long uptimeSeconds
+        long uptimeSeconds,
+        @Schema(description = "Recent average CPU usage (0.0–1.0), -1 if unavailable") double cpuUsage
 ) {
     public static AgentInstanceResponse from(AgentInfo info) {
         long uptime = Duration.between(info.registeredAt(), Instant.now()).toSeconds();
@@ -37,7 +38,7 @@ public record AgentInstanceResponse(
                 info.version(), info.capabilities(),
                 0.0, 0.0,
                 0, info.routeIds() != null ? info.routeIds().size() : 0,
-                uptime
+                uptime, -1
         );
     }
 
@@ -46,7 +47,16 @@ public record AgentInstanceResponse(
                 instanceId, displayName, applicationId, environmentId,
                 status, routeIds, registeredAt, lastHeartbeat,
                 version, capabilities,
-                tps, errorRate, activeRoutes, totalRoutes, uptimeSeconds
+                tps, errorRate, activeRoutes, totalRoutes, uptimeSeconds, cpuUsage
+        );
+    }
+
+    public AgentInstanceResponse withCpuUsage(double cpuUsage) {
+        return new AgentInstanceResponse(
+                instanceId, displayName, applicationId, environmentId,
+                status, routeIds, registeredAt, lastHeartbeat,
+                version, capabilities,
+                tps, errorRate, activeRoutes, totalRoutes, uptimeSeconds, cpuUsage
         );
     }
 }