Add App I/O selection system (#8965)

Adds a system for selecting the inputs and outputs which should be
displayed when inside linear mode. Functions only in litegraph
currently. Vue support will require a separate, larger PR.
Inputs and outputs can be re-ordered by dragging and dropping on the
side panel.

![builder_00001](https://github.com/user-attachments/assets/6345adbd-519e-455d-b71e-0020aa03c6b7)

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8965-Add-App-I-O-selection-system-30b6d73d365081569b36c1682a1fdbc5)
by [Unito](https://www.unito.io)

src/components/common/DraggableList.vue

@@ -0,0 +1,59 @@
+<script setup lang="ts" generic="T">
+import { onBeforeUnmount, ref, useTemplateRef, watchPostEffect } from 'vue'
+
+import { DraggableList } from '@/scripts/ui/draggableList'
+
+const modelValue = defineModel<T[]>({ required: true })
+const draggableList = ref<DraggableList>()
+const draggableItems = useTemplateRef('draggableItems')
+
+watchPostEffect(() => {
+  void modelValue.value.length
+  draggableList.value?.dispose()
+  if (!draggableItems.value?.children?.length) return
+  draggableList.value = new DraggableList(
+    draggableItems.value,
+    '.draggable-item'
+  )
+  draggableList.value.applyNewItemsOrder = function () {
+    const reorderedItems = []
+
+    let oldPosition = -1
+    this.getAllItems().forEach((item, index) => {
+      if (item === this.draggableItem) {
+        oldPosition = index
+        return
+      }
+      if (!this.isItemToggled(item)) {
+        reorderedItems[index] = item
+        return
+      }
+      const newIndex = this.isItemAbove(item) ? index + 1 : index - 1
+      reorderedItems[newIndex] = item
+    })
+
+    for (let index = 0; index < this.getAllItems().length; index++) {
+      const item = reorderedItems[index]
+      if (typeof item === 'undefined') {
+        reorderedItems[index] = this.draggableItem
+      }
+    }
+    const newPosition = reorderedItems.indexOf(this.draggableItem)
+    const itemList = modelValue.value
+    const [item] = itemList.splice(oldPosition, 1)
+    itemList.splice(newPosition, 0, item)
+    modelValue.value = [...itemList]
+  }
+})
+
+onBeforeUnmount(() => {
+  draggableList.value?.dispose()
+})
+</script>
+<template>
+  <div ref="draggableItems" class="pb-2 px-2 space-y-0.5 mt-0.5">
+    <slot
+      drag-class="draggable-item drag-handle cursor-grab [&.is-draggable]:cursor-grabbing"
+    />
+  </div>
+</template>