feat: Complete fleet — 94 skills across 10+ domains

Pulled ALL skills from 15 source repositories:
- anthropics/skills: 16 (docs, design, MCP, testing)
- obra/superpowers: 14 (TDD, debugging, agents, planning)
- coreyhaines31/marketingskills: 25 (marketing, CRO, SEO, growth)
- better-auth/skills: 5 (auth patterns)
- vercel-labs/agent-skills: 5 (React, design, Vercel)
- antfu/skills: 16 (Vue, Vite, Vitest, pnpm, Turborepo)
- Plus 13 individual skills from various repos

Mosaic Stack is not limited to coding — the Orchestrator and
subagents serve coding, business, design, marketing, writing,
logistics, analysis, and more.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

skills/vueuse-functions/references/useDocumentVisibility.md

@@ -0,0 +1,45 @@
+---
+category: Elements
+---
+
+# useDocumentVisibility
+
+Reactively track [`document.visibilityState`](https://developer.mozilla.org/en-US/docs/Web/API/Document/visibilityState)
+
+## Usage
+
+```vue
+<script setup lang="ts">
+import { useDocumentVisibility } from '@vueuse/core'
+
+const visibility = useDocumentVisibility()
+</script>
+```
+
+## Component Usage
+
+```vue
+<template>
+  <UseDocumentVisibility v-slot="{ visibility }">
+    Document Visibility: {{ visibility }}
+  </UseDocumentVisibility>
+</template>
+```
+
+## Type Declarations
+
+```ts
+/**
+ * Reactively track `document.visibilityState`.
+ *
+ * @see https://vueuse.org/useDocumentVisibility
+ *
+ * @__NO_SIDE_EFFECTS__
+ */
+export declare function useDocumentVisibility(
+  options?: ConfigurableDocument,
+): ShallowRef<string, string>
+export type UseDocumentVisibilityReturn = ReturnType<
+  typeof useDocumentVisibility
+>
+```