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/useShare.md

@@ -0,0 +1,67 @@
+---
+category: Browser
+---
+
+# useShare
+
+Reactive [Web Share API](https://developer.mozilla.org/en-US/docs/Web/API/Navigator/share). The Browser provides features that can share content in text or file.
+
+> The `share` method has to be called following a user gesture like a button click. It can’t simply be called on page load for example. That’s in place to help prevent abuse.
+
+## Usage
+
+```ts
+import { useShare } from '@vueuse/core'
+
+const { share, isSupported } = useShare()
+
+function startShare() {
+  share({
+    title: 'Hello',
+    text: 'Hello my friend!',
+    url: location.href,
+  })
+}
+```
+
+### Passing a source ref
+
+You can pass a `ref` to it, changes from the source ref will be reflected to your sharing options.
+
+```ts {6}
+import { ref } from 'vue'
+
+const shareOptions = ref<ShareOptions>({ text: 'foo' })
+const { share, isSupported } = useShare(shareOptions)
+
+shareOptions.value.text = 'bar'
+
+share()
+```
+
+## Type Declarations
+
+```ts
+export interface UseShareOptions {
+  title?: string
+  files?: File[]
+  text?: string
+  url?: string
+}
+export interface UseShareReturn extends Supportable {
+  share: (overrideOptions?: MaybeRefOrGetter<UseShareOptions>) => Promise<void>
+}
+/**
+ * Reactive Web Share API.
+ *
+ * @see https://vueuse.org/useShare
+ * @param shareOptions
+ * @param options
+ *
+ * @__NO_SIDE_EFFECTS__
+ */
+export declare function useShare(
+  shareOptions?: MaybeRefOrGetter<UseShareOptions>,
+  options?: ConfigurableNavigator,
+): UseShareReturn
+```