docs: add advanced skills for Vitest, Pinia, and Vue built-ins

Add comprehensive reference documentation for:
- Vitest: environments, projects/workspaces, type testing, vi utilities
- Pinia: HMR, Nuxt integration, SSR setup
- Vue: built-in components (Transition, Teleport, Suspense, KeepAlive) and advanced directives

.agents/skills/vueuse-functions/references/useArrayUnique.md

@@ -0,0 +1,76 @@
+---
+category: Array
+---
+
+# useArrayUnique
+
+reactive unique array
+
+## Usage
+
+### Use with array of multiple refs
+
+```ts
+import { useArrayUnique } from '@vueuse/core'
+
+const item1 = ref(0)
+const item2 = ref(1)
+const item3 = ref(1)
+const item4 = ref(2)
+const item5 = ref(3)
+const list = [item1, item2, item3, item4, item5]
+const result = useArrayUnique(list)
+// result.value: [0, 1, 2, 3]
+item5.value = 1
+// result.value: [0, 1, 2]
+```
+
+### Use with reactive array
+
+```ts
+import { useArrayUnique } from '@vueuse/core'
+
+const list = reactive([1, 2, 2, 3])
+const result = useArrayUnique(list)
+// result.value: [1, 2, 3]
+
+list.push(1)
+// result.value: [1, 2, 3]
+```
+
+### Use with custom function
+
+```ts
+import { useArrayUnique } from '@vueuse/core'
+
+const list = reactive([
+  { id: 1, name: 'foo' },
+  { id: 2, name: 'bar' },
+  { id: 1, name: 'baz' },
+])
+
+const result = useArrayUnique(list, (a, b) => a.id === b.id)
+// result.value: [{ id: 1, name: 'foo' }, { id: 2, name: 'bar' }]
+
+list.push({ id: 1, name: 'qux' })
+// result.value: [{ id: 1, name: 'foo' }, { id: 2, name: 'bar' }]
+```
+
+## Type Declarations
+
+```ts
+export type UseArrayUniqueReturn<T = any> = ComputedRef<T[]>
+/**
+ * reactive unique array
+ * @see https://vueuse.org/useArrayUnique
+ * @param list - the array was called upon.
+ * @param compareFn
+ * @returns A computed ref that returns a unique array of items.
+ *
+ * @__NO_SIDE_EFFECTS__
+ */
+export declare function useArrayUnique<T>(
+  list: MaybeRefOrGetter<MaybeRefOrGetter<T>[]>,
+  compareFn?: (a: T, b: T, array: T[]) => boolean,
+): UseArrayUniqueReturn<T>
+```