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/useIDBKeyval.md

@@ -0,0 +1,93 @@
+---
+category: '@Integrations'
+---
+
+# useIDBKeyval
+
+Wrapper for [`idb-keyval`](https://www.npmjs.com/package/idb-keyval).
+
+## Install idb-keyval as a peer dependency
+
+```bash
+npm install idb-keyval@^6
+```
+
+## Usage
+
+```ts
+import { useIDBKeyval } from '@vueuse/integrations/useIDBKeyval'
+
+// bind object
+const { data: storedObject, isFinished } = useIDBKeyval('my-idb-keyval-store', { hello: 'hi', greeting: 'Hello' })
+
+// update object
+storedObject.value.hello = 'hola'
+
+// bind boolean
+const flag = useIDBKeyval('my-flag', true) // returns Ref<boolean>
+
+// bind number
+const count = useIDBKeyval('my-count', 0) // returns Ref<number>
+
+// awaiting IDB transaction
+await count.set(10)
+console.log('IDB transaction finished!')
+
+// delete data from idb storage
+storedObject.value = null
+```
+
+## Type Declarations
+
+```ts
+interface Serializer<T> {
+  read: (raw: unknown) => T
+  write: (value: T) => unknown
+}
+export interface UseIDBOptions<T> extends ConfigurableFlush {
+  /**
+   * Watch for deep changes
+   *
+   * @default true
+   */
+  deep?: boolean
+  /**
+   * On error callback
+   *
+   * Default log error to `console.error`
+   */
+  onError?: (error: unknown) => void
+  /**
+   * Use shallow ref as reference
+   *
+   * @default false
+   */
+  shallow?: boolean
+  /**
+   * Write the default value to the storage when it does not exist
+   *
+   * @default true
+   */
+  writeDefaults?: boolean
+  /**
+   * Custom data serialization
+   */
+  serializer?: Serializer<T>
+}
+export interface UseIDBKeyvalReturn<T> {
+  data: RemovableRef<T>
+  isFinished: ShallowRef<boolean>
+  set: (value: T) => Promise<void>
+}
+/**
+ *
+ * @param key
+ * @param initialValue
+ * @param options
+ */
+export declare function useIDBKeyval<T>(
+  key: IDBValidKey,
+  initialValue: MaybeRefOrGetter<T>,
+  options?: UseIDBOptions<T>,
+): UseIDBKeyvalReturn<T>
+```