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/useTextSelection.md

@@ -0,0 +1,43 @@
+---
+category: Sensors
+---
+
+# useTextSelection
+
+Reactively track user text selection based on [`Window.getSelection`](https://developer.mozilla.org/en-US/docs/Web/API/Window/getSelection).
+
+## Usage
+
+```vue
+<script setup lang="ts">
+import { useTextSelection } from '@vueuse/core'
+
+const state = useTextSelection()
+</script>
+
+<template>
+  <p>{{ state.text }}</p>
+</template>
+```
+
+## Type Declarations
+
+```ts
+export interface UseTextSelectionOptions extends ConfigurableWindow {}
+export interface UseTextSelectionReturn {
+  text: ComputedRef<string>
+  rects: ComputedRef<DOMRect[]>
+  ranges: ComputedRef<Range[]>
+  selection: ShallowRef<Selection | null>
+}
+/**
+ * Reactively track user text selection based on [`Window.getSelection`](https://developer.mozilla.org/en-US/docs/Web/API/Window/getSelection).
+ *
+ * @see https://vueuse.org/useTextSelection
+ *
+ * @__NO_SIDE_EFFECTS__
+ */
+export declare function useTextSelection(
+  options?: UseTextSelectionOptions,
+): UseTextSelectionReturn
+```