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/tryOnUnmounted.md

@@ -0,0 +1,32 @@
+---
+category: Component
+---
+
+# tryOnUnmounted
+
+Safe `onUnmounted`. Call `onUnmounted()` if it's inside a component lifecycle, if not, do nothing
+
+## Usage
+
+```ts
+import { tryOnUnmounted } from '@vueuse/core'
+
+tryOnUnmounted(() => {
+
+})
+```
+
+## Type Declarations
+
+```ts
+/**
+ * Call onUnmounted() if it's inside a component lifecycle, if not, do nothing
+ *
+ * @param fn
+ * @param target
+ */
+export declare function tryOnUnmounted(
+  fn: Fn,
+  target?: ComponentInternalInstance | null,
+): void
+```