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/pages/Admin/AppConfigPage.tsx

@@ -1,14 +1,12 @@
 import { useState, useMemo, useEffect } from 'react';
 import { useNavigate } from 'react-router';
-import { useQueries } from '@tanstack/react-query';
 import {
   DataTable, Badge, MonoText, DetailPanel, SectionHeader, Button, Toggle, Spinner, useToast,
 } from '@cameleer/design-system';
 import type { Column } from '@cameleer/design-system';
-import { useAllApplicationConfigs, useApplicationConfig, useUpdateApplicationConfig } from '../../api/queries/commands';
+import { useAllApplicationConfigs, useApplicationConfig, useUpdateApplicationConfig, useProcessorRouteMapping } from '../../api/queries/commands';
 import type { ApplicationConfig, TapDefinition } from '../../api/queries/commands';
 import { useRouteCatalog } from '../../api/queries/catalog';
-import { api } from '../../api/client';
 import type { AppCatalogEntry, RouteSummary } from '../../api/types';
 import styles from './AppConfigPage.module.css';
 
@@ -87,32 +85,8 @@ function AppConfigDetail({ appId, onClose }: { appId: string; onClose: () => voi
     return entry?.routes ?? [];
   }, [catalog, appId]);
 
-  // Fetch diagrams for all routes to build processorId → routeId mapping
-  const diagramQueries = useQueries({
-    queries: appRoutes.map((r) => ({
-      queryKey: ['diagrams', 'byRoute', appId, r.routeId],
-      queryFn: async () => {
-        const { data, error } = await api.GET('/diagrams', {
-          params: { query: { application: appId!, routeId: r.routeId } },
-        });
-        if (error) return { routeId: r.routeId, nodes: [] as Array<{ id?: string }> };
-        return { routeId: r.routeId, nodes: (data as any)?.nodes ?? [] };
-      },
-      enabled: !!appId,
-      staleTime: 60_000,
-    })),
-  });
-
-  const processorToRoute = useMemo(() => {
-    const map: Record<string, string> = {};
-    for (const q of diagramQueries) {
-      if (!q.data) continue;
-      for (const node of q.data.nodes) {
-        if (node.id) map[node.id] = q.data.routeId;
-      }
-    }
-    return map;
-  }, [diagramQueries.map(q => q.data)]);
+  // processorId → routeId mapping from backend
+  const { data: processorToRoute = {} } = useProcessorRouteMapping(appId);
 
   useEffect(() => {
     if (config) {