feat: add node group breadcrumbs

app/src/lib/sidebar/panels/GroupSettings.svelte

@@ -2,6 +2,7 @@
   import type { GraphManager } from '$lib/graph-interface/graph-manager.svelte';
   import type { NodeInstance } from '@nodarium/types';
   import InputSelect from '../../../../../packages/ui/src/lib/inputs/InputSelect.svelte';
+  import UnusedGroupsPanel from './UnusedGroupsPanel.svelte';
 
   type Props = {
     manager: GraphManager;
@@ -28,18 +29,9 @@
     const name = (e.target as HTMLInputElement).value;
     if (activeGroup) manager.renameGroup(activeGroup.id, name);
   }
-
-  const hasUnusedGroups = $derived.by(() => {
-    if (!manager) return false;
-    if (manager.isInsideGroup) return false;
-    if (manager.graph.groups.length === 0) return false;
-    return manager.graph.groups.filter(g => {
-      return !manager.graph.nodes.find(n => n.props?.groupId === g.id);
-    }).length;
-  });
 </script>
 
-{#if activeGroup || hasUnusedGroups}
+{#if activeGroup}
   <div class='{node?"border-l-2 pl-3.5!":""} bg-layer-2 flex items-center h-[70px] border-b-1 border-l-selected border-b-outline pl-4'>
     <h3>Group Settings</h3>
   </div>
@@ -76,12 +68,8 @@
   {/key}
 {/if}
 
-{#if hasUnusedGroups}
-  <div class="group-actions">
-    <button onclick={() => manager.removeUnusedGroups()}>
-      Remove ({hasUnusedGroups}) orphaned groups
-    </button>
-  </div>
+{#if manager && !manager.isInsideGroup}
+  <UnusedGroupsPanel {manager} />
 {/if}
 
 <style>
@@ -110,26 +98,4 @@
   .group-settings input:focus {
     outline: 1px solid var(--color-active);
   }
-
-  .group-actions {
-    padding: 0.75em 1em;
-    border-bottom: 1px solid var(--color-outline);
-    margin-top: auto;
-  }
-
-  .group-actions button {
-    width: 100%;
-    padding: 0.4em 0.8em;
-    background: var(--color-layer-1);
-    border: 1px solid var(--color-outline);
-    border-radius: 4px;
-    color: var(--color-text);
-    font-family: var(--font-family);
-    font-size: 0.85em;
-    cursor: pointer;
-  }
-
-  .group-actions button:hover {
-    border-color: var(--color-active);
-  }
 </style>

app/src/lib/sidebar/panels/UnusedGroupsPanel.svelte

@@ -0,0 +1,134 @@
+<script lang="ts">
+  import type { GraphManager } from '$lib/graph-interface/graph-manager.svelte';
+  import type { GroupDefinition } from '@nodarium/types';
+  import { SvelteMap, SvelteSet } from 'svelte/reactivity';
+
+  type Props = { manager: GraphManager };
+  const { manager }: Props = $props();
+
+  type GroupNode = { group: GroupDefinition; children: GroupNode[] };
+
+  const unusedTree = $derived.by((): GroupNode[] => {
+    const unused = manager.getUnusedGroups();
+    if (!unused.length) return [];
+
+    const unusedIds = new Set(unused.map(g => g.id));
+
+    // Build child map: which unused groups reference which other unused groups
+    const childrenOf = new SvelteMap<number, number[]>();
+    const referencedBy = new SvelteSet<number>();
+
+    for (const group of unused) {
+      const refs: number[] = [];
+      for (const node of group.nodes) {
+        if (node.type === '__internal/group/instance' && node.props?.groupId !== undefined) {
+          const childId = node.props.groupId as number;
+          if (unusedIds.has(childId)) {
+            refs.push(childId);
+            referencedBy.add(childId);
+          }
+        }
+      }
+      childrenOf.set(group.id, refs);
+    }
+
+    const byId = new Map(unused.map(g => [g.id, g]));
+
+    function buildNode(g: GroupDefinition): GroupNode {
+      return {
+        group: g,
+        children: (childrenOf.get(g.id) ?? []).map(id => buildNode(byId.get(id)!))
+      };
+    }
+
+    return unused
+      .filter(g => !referencedBy.has(g.id))
+      .map(buildNode);
+  });
+</script>
+
+{#if unusedTree.length}
+  <div class="panel">
+    <div class="header">
+      <span>Unused groups</span>
+      <button class="remove-all" onclick={() => manager.removeUnusedGroups()}>
+        Remove all
+      </button>
+    </div>
+
+    <ul class="tree">
+      {#snippet treeNode(node: GroupNode)}
+        <li>
+          <span class="group-name">{node.group.name || `Group #${node.group.id}`}</span>
+          {#if node.children.length}
+            <ul>
+              {#each node.children as child (child.group.id)}
+                {@render treeNode(child)}
+              {/each}
+            </ul>
+          {/if}
+        </li>
+      {/snippet}
+      {#each unusedTree as node (node.group.id)}
+        {@render treeNode(node)}
+      {/each}
+    </ul>
+  </div>
+{/if}
+
+<style>
+  .panel {
+    border-bottom: 1px solid var(--color-outline);
+    padding: 0.75em 1em;
+  }
+
+  .header {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    margin-bottom: 0.5em;
+    font-size: 0.8em;
+    opacity: 0.7;
+  }
+
+  .remove-all {
+    background: none;
+    border: 1px solid var(--color-outline);
+    border-radius: 4px;
+    color: var(--color-text);
+    cursor: pointer;
+    font-family: var(--font-family);
+    font-size: 0.85em;
+    padding: 0.2em 0.5em;
+  }
+
+  .remove-all:hover {
+    border-color: var(--color-active);
+  }
+
+  .tree {
+    list-style: none;
+    margin: 0;
+    padding: 0;
+  }
+
+  .tree ul {
+    list-style: none;
+    margin: 0;
+    padding-left: 1.2em;
+    border-left: 1px solid var(--color-outline);
+  }
+
+  .tree li {
+    padding: 0.15em 0;
+  }
+
+  .group-name {
+    font-size: 0.85em;
+  }
+
+  .tree ul .group-name::before {
+    content: '└ ';
+    opacity: 0.4;
+  }
+</style>