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/useElementByPoint.md

@@ -0,0 +1,46 @@
+---
+category: Sensors
+---
+
+# useElementByPoint
+
+Reactive element by point.
+
+## Usage
+
+```ts
+import { useElementByPoint, useMouse } from '@vueuse/core'
+
+const { x, y } = useMouse({ type: 'client' })
+const { element } = useElementByPoint({ x, y })
+```
+
+## Type Declarations
+
+```ts
+export interface UseElementByPointOptions<Multiple extends boolean = false>
+  extends ConfigurableDocument, ConfigurableScheduler {
+  x: MaybeRefOrGetter<number>
+  y: MaybeRefOrGetter<number>
+  multiple?: MaybeRefOrGetter<Multiple>
+  /** @deprecated Please use `scheduler` option instead */
+  immediate?: boolean
+  /** @deprecated Please use `scheduler` option instead */
+  interval?: "requestAnimationFrame" | number
+}
+export interface UseElementByPointReturn<Multiple extends boolean = false>
+  extends Supportable, Pausable {
+  element: ShallowRef<
+    Multiple extends true ? HTMLElement[] : HTMLElement | null
+  >
+}
+/**
+ * Reactive element by point.
+ *
+ * @see https://vueuse.org/useElementByPoint
+ * @param options - UseElementByPointOptions
+ */
+export declare function useElementByPoint<M extends boolean = false>(
+  options: UseElementByPointOptions<M>,
+): UseElementByPointReturn<M>
+```