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/useRouteHash.md

@@ -0,0 +1,27 @@
+---
+category: '@Router'
+---
+
+# useRouteHash
+
+Shorthand for a reactive `route.hash`.
+
+## Usage
+
+```ts
+import { useRouteHash } from '@vueuse/router'
+
+const search = useRouteHash()
+
+console.log(search.value) // route.hash
+search.value = 'foobar' // router.replace({ hash: 'foobar' })
+```
+
+## Type Declarations
+
+```ts
+export declare function useRouteHash(
+  defaultValue?: MaybeRefOrGetter<RouteHashValueRaw>,
+  { mode, route, router }?: ReactiveRouteOptions,
+): Ref<RouteHashValueRaw, RouteHashValueRaw>
+```