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/onStartTyping.md

@@ -0,0 +1,53 @@
+---
+category: Sensors
+---
+
+# onStartTyping
+
+Fires when users start typing on non-editable elements. Useful for auto-focusing an input field when the user starts typing anywhere on the page.
+
+## Usage
+
+```vue
+<script setup lang="ts">
+import { onStartTyping } from '@vueuse/core'
+import { useTemplateRef } from 'vue'
+
+const input = useTemplateRef('input')
+
+onStartTyping(() => {
+  if (!input.value.active)
+    input.value.focus()
+})
+</script>
+
+<template>
+  <input ref="input" type="text" placeholder="Start typing to focus">
+</template>
+```
+
+## How It Works
+
+The callback only fires when:
+
+- No editable element (`<input>`, `<textarea>`, or `contenteditable`) is focused
+- The pressed key is alphanumeric (A-Z, 0-9)
+- No modifier keys (Ctrl, Alt, Meta) are held
+
+This allows users to start typing anywhere on the page without accidentally triggering the callback when using keyboard shortcuts or interacting with form fields.
+
+## Type Declarations
+
+```ts
+/**
+ * Fires when users start typing on non-editable elements.
+ *
+ * @see https://vueuse.org/onStartTyping
+ * @param callback
+ * @param options
+ */
+export declare function onStartTyping(
+  callback: (event: KeyboardEvent) => void,
+  options?: ConfigurableDocument,
+): void
+```