fix: add precedes graph edge from classification to execution

Every run call creates a classification entity, but it was never
connected to the execution via a graph edge — only via a DB column
(executions.classification_id). The ontology requires:

    classification —precedes→ execution

Without this edge, all 53 classification entities had zero
relationships, making them invisible to get_relations and
blast-radius analysis.

Adds an idempotent INSERT into relationships after the existing
classification_id update, matching the same pattern used for
targets edges.

web/src/lib/apps.ts

@@ -38,6 +38,7 @@ import TrendingUpIcon from '@lucide/svelte/icons/trending-up'
 import SettingsIcon from '@lucide/svelte/icons/settings'
 import EggIcon from '@lucide/svelte/icons/egg'
 import StoreIcon from '@lucide/svelte/icons/store'
+import Share2Icon from '@lucide/svelte/icons/share-2'
 
 export type { AppManifest, AppPermission }
 
@@ -180,6 +181,17 @@ export const builtinApps: AppDef[] = [
     component: () => import('./mascot/MascotLayer.svelte'),
     docked: true,
     source: 'builtin'
+  },
+  {
+    id: 'entity-graph',
+    title: 'Entity Graph',
+    icon: Share2Icon,
+    component: () => import('../pages/EntityGraph.svelte'),
+    width: 1100,
+    height: 750,
+    minWidth: 640,
+    minHeight: 420,
+    source: 'builtin'
   }
 ]