refactor: remove diagramNodeId indirection, use processorId directly

Agent now uses Camel processorId as RouteNode.id, eliminating the
nodeId mapping layer. Drop diagram_node_id column (V6 migration),
remove from ProcessorRecord/ProcessorNode/IngestionService/DetailService,
add /processor-routes endpoint for processorId→routeId lookup,
simplify frontend diagram-mapping and ExchangeDetail overlays,
replace N diagram fetches in AppConfigPage with single hook.

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

cameleer3-server-app/src/main/java/com/cameleer3/server/app/controller/ApplicationConfigController.java

@@ -13,6 +13,7 @@ import com.cameleer3.server.core.agent.AgentRegistryService;
 import com.cameleer3.server.core.agent.AgentState;
 import com.cameleer3.server.core.agent.CommandReply;
 import com.cameleer3.server.core.agent.CommandType;
+import com.cameleer3.server.core.storage.ExecutionStore;
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import io.swagger.v3.oas.annotations.Operation;
@@ -48,15 +49,18 @@ public class ApplicationConfigController {
     private final AgentRegistryService registryService;
     private final ObjectMapper objectMapper;
     private final AuditService auditService;
+    private final ExecutionStore executionStore;
 
     public ApplicationConfigController(PostgresApplicationConfigRepository configRepository,
                                        AgentRegistryService registryService,
                                        ObjectMapper objectMapper,
-                                       AuditService auditService) {
+                                       AuditService auditService,
+                                       ExecutionStore executionStore) {
         this.configRepository = configRepository;
         this.registryService = registryService;
         this.objectMapper = objectMapper;
         this.auditService = auditService;
+        this.executionStore = executionStore;
     }
 
     @GetMapping
@@ -103,6 +107,14 @@ public class ApplicationConfigController {
         return ResponseEntity.ok(saved);
     }
 
+    @GetMapping("/{application}/processor-routes")
+    @Operation(summary = "Get processor to route mapping",
+            description = "Returns a map of processorId → routeId for all processors seen in this application")
+    @ApiResponse(responseCode = "200", description = "Mapping returned")
+    public ResponseEntity<Map<String, String>> getProcessorRouteMapping(@PathVariable String application) {
+        return ResponseEntity.ok(executionStore.findProcessorRouteMapping(application));
+    }
+
     @PostMapping("/{application}/test-expression")
     @Operation(summary = "Test a tap expression against sample data via a live agent")
     @ApiResponse(responseCode = "200", description = "Expression evaluated successfully")