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/tryOnBeforeMount.md

@@ -0,0 +1,34 @@
+---
+category: Component
+---
+
+# tryOnBeforeMount
+
+Safe `onBeforeMount`. Call `onBeforeMount()` if it's inside a component lifecycle, if not, just call the function
+
+## Usage
+
+```ts
+import { tryOnBeforeMount } from '@vueuse/core'
+
+tryOnBeforeMount(() => {
+
+})
+```
+
+## Type Declarations
+
+```ts
+/**
+ * Call onBeforeMount() if it's inside a component lifecycle, if not, just call the function
+ *
+ * @param fn
+ * @param sync if set to false, it will run in the nextTick() of Vue
+ * @param target
+ */
+export declare function tryOnBeforeMount(
+  fn: Fn,
+  sync?: boolean,
+  target?: ComponentInternalInstance | null,
+): void
+```