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/useElementHover.md

@@ -0,0 +1,79 @@
+---
+category: Sensors
+---
+
+# useElementHover
+
+Reactive element's hover state.
+
+## Usage
+
+```vue
+<script setup lang="ts">
+import { useElementHover } from '@vueuse/core'
+import { useTemplateRef } from 'vue'
+
+const myHoverableElement = useTemplateRef('myHoverableElement')
+const isHovered = useElementHover(myHoverableElement)
+</script>
+
+<template>
+  <button ref="myHoverableElement">
+    {{ isHovered }}
+  </button>
+</template>
+```
+
+## Directive Usage
+
+```vue
+<script setup lang="ts">
+import { vElementHover } from '@vueuse/components'
+import { shallowRef } from 'vue'
+
+const isHovered = shallowRef(false)
+function onHover(state: boolean) {
+  isHovered.value = state
+}
+</script>
+
+<template>
+  <button v-element-hover="onHover">
+    {{ isHovered ? 'Thank you!' : 'Hover me' }}
+  </button>
+</template>
+```
+
+You can also provide hover options:
+
+```vue
+<script setup lang="ts">
+import { vElementHover } from '@vueuse/components'
+import { shallowRef } from 'vue'
+
+const isHovered = shallowRef(false)
+function onHover(hovered: boolean) {
+  isHovered.value = hovered
+}
+</script>
+
+<template>
+  <button v-element-hover="[onHover, { delayEnter: 1000 }]">
+    <span>{{ isHovered ? 'Thank you!' : 'Hover me' }}</span>
+  </button>
+</template>
+```
+
+## Type Declarations
+
+```ts
+export interface UseElementHoverOptions extends ConfigurableWindow {
+  delayEnter?: number
+  delayLeave?: number
+  triggerOnRemoval?: boolean
+}
+export declare function useElementHover(
+  el: MaybeRefOrGetter<EventTarget | null | undefined>,
+  options?: UseElementHoverOptions,
+): ShallowRef<boolean>
+```