feat: rename agent identity fields for protocol v2 + add SHUTDOWN lifecycle state

Align all internal naming with the agent team's protocol v2 identity rename:
- agentId → instanceId (unique per-JVM identifier)
- applicationName → applicationId (shared app identifier)
- AgentInfo: id → instanceId, name → displayName, application → applicationId

Add SHUTDOWN lifecycle state for graceful agent shutdowns:
- New POST /data/events endpoint receives agent lifecycle events
- AGENT_STOPPED event transitions agent to SHUTDOWN (skips STALE/DEAD)
- New POST /{id}/deregister endpoint removes agent from registry
- Server now distinguishes graceful shutdown from crash (heartbeat timeout)

Includes ClickHouse V9 and PostgreSQL V14 migrations for column renames.

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

cameleer3-server-app/src/main/java/com/cameleer3/server/app/dto/AgentEventResponse.java

@@ -9,15 +9,15 @@ import java.time.Instant;
 @Schema(description = "Agent lifecycle event")
 public record AgentEventResponse(
         @NotNull long id,
-        @NotNull String agentId,
-        @NotNull String appId,
+        @NotNull String instanceId,
+        @NotNull String applicationId,
         @NotNull String eventType,
         String detail,
         @NotNull Instant timestamp
 ) {
     public static AgentEventResponse from(AgentEventRecord record) {
         return new AgentEventResponse(
-                record.id(), record.agentId(), record.appId(),
+                record.id(), record.instanceId(), record.applicationId(),
                 record.eventType(), record.detail(), record.timestamp()
         );
     }

cameleer3-server-app/src/main/java/com/cameleer3/server/app/dto/AgentInstanceResponse.java

@@ -11,9 +11,9 @@ import java.util.Map;
 
 @Schema(description = "Agent instance summary with runtime metrics")
 public record AgentInstanceResponse(
-        @NotNull String id,
-        @NotNull String name,
-        @NotNull String application,
+        @NotNull String instanceId,
+        @NotNull String displayName,
+        @NotNull String applicationId,
         @NotNull String status,
         @NotNull List<String> routeIds,
         @NotNull Instant registeredAt,
@@ -29,7 +29,7 @@ public record AgentInstanceResponse(
     public static AgentInstanceResponse from(AgentInfo info) {
         long uptime = Duration.between(info.registeredAt(), Instant.now()).toSeconds();
         return new AgentInstanceResponse(
-                info.id(), info.name(), info.application(),
+                info.instanceId(), info.displayName(), info.applicationId(),
                 info.state().name(), info.routeIds(),
                 info.registeredAt(), info.lastHeartbeat(),
                 info.version(), info.capabilities(),
@@ -41,7 +41,7 @@ public record AgentInstanceResponse(
 
     public AgentInstanceResponse withMetrics(double tps, double errorRate, int activeRoutes) {
         return new AgentInstanceResponse(
-                id, name, application, status, routeIds, registeredAt, lastHeartbeat,
+                instanceId, displayName, applicationId, status, routeIds, registeredAt, lastHeartbeat,
                 version, capabilities,
                 tps, errorRate, activeRoutes, totalRoutes, uptimeSeconds
         );

cameleer3-server-app/src/main/java/com/cameleer3/server/app/dto/AgentRegistrationRequest.java

@@ -8,9 +8,9 @@ import java.util.Map;
 
 @Schema(description = "Agent registration payload")
 public record AgentRegistrationRequest(
-        @NotNull String agentId,
-        @NotNull String name,
-        @Schema(defaultValue = "default") String application,
+        @NotNull String instanceId,
+        @NotNull String displayName,
+        @Schema(defaultValue = "default") String applicationId,
         String version,
         List<String> routeIds,
         Map<String, Object> capabilities

cameleer3-server-app/src/main/java/com/cameleer3/server/app/dto/AgentRegistrationResponse.java

@@ -5,7 +5,7 @@ import jakarta.validation.constraints.NotNull;
 
 @Schema(description = "Agent registration result with JWT tokens and SSE endpoint")
 public record AgentRegistrationResponse(
-        @NotNull String agentId,
+        @NotNull String instanceId,
         @NotNull String sseEndpoint,
         long heartbeatIntervalMs,
         @NotNull String serverPublicKey,