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>

ui/src/utils/diagram-mapping.ts

@@ -20,11 +20,11 @@ function mapStatus(status: string | undefined): RouteNode['status'] {
 
 /**
  * Maps diagram PositionedNodes + execution ProcessorNodes to RouteFlow RouteNode[] format.
- * Joins on diagramNodeId → node.id.
+ * Joins on processorId → node.id (node IDs are Camel processor IDs).
  */
 export function mapDiagramToRouteNodes(
   diagramNodes: Array<{ id?: string; label?: string; type?: string }>,
-  processors: Array<{ diagramNodeId?: string; processorId?: string; status?: string; durationMs?: number; children?: any[] }>
+  processors: Array<{ processorId?: string; status?: string; durationMs?: number; children?: any[] }>
 ): RouteNode[] {
   // Flatten processor tree
   const flatProcessors: typeof processors = [];
@@ -36,10 +36,10 @@ export function mapDiagramToRouteNodes(
   }
   flatten(processors || []);
 
-  // Build lookup: diagramNodeId → processor
+  // Build lookup: processorId → processor
   const procMap = new Map<string, (typeof flatProcessors)[0]>();
   for (const p of flatProcessors) {
-    if (p.diagramNodeId) procMap.set(p.diagramNodeId, p);
+    if (p.processorId) procMap.set(p.processorId, p);
   }
 
   return diagramNodes.map(node => {