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/useTimeoutPoll.md

@@ -0,0 +1,47 @@
+---
+category: Utilities
+---
+
+# useTimeoutPoll
+
+Use timeout to poll something. It will trigger callback after last task is done.
+
+## Usage
+
+```ts
+import { useTimeoutPoll } from '@vueuse/core'
+
+const count = ref(0)
+
+async function fetchData() {
+  await new Promise(resolve => setTimeout(resolve, 1000))
+  count.value++
+}
+
+// Only trigger after last fetch is done
+const { isActive, pause, resume } = useTimeoutPoll(fetchData, 1000)
+```
+
+## Type Declarations
+
+```ts
+export interface UseTimeoutPollOptions {
+  /**
+   * Start the timer immediately
+   *
+   * @default true
+   */
+  immediate?: boolean
+  /**
+   * Execute the callback immediately after calling `resume`
+   *
+   * @default false
+   */
+  immediateCallback?: boolean
+}
+export declare function useTimeoutPoll(
+  fn: () => Awaitable<void>,
+  interval: MaybeRefOrGetter<number>,
+  options?: UseTimeoutFnOptions,
+): Pausable
+```