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/usePrevious.md

@@ -0,0 +1,40 @@
+---
+category: Utilities
+---
+
+# usePrevious
+
+Holds the previous value of a ref.
+
+## Usage
+
+```ts
+import { usePrevious } from '@vueuse/core'
+import { shallowRef } from 'vue'
+
+const counter = shallowRef('Hello')
+const previous = usePrevious(counter)
+
+console.log(previous.value) // undefined
+
+counter.value = 'World'
+
+console.log(previous.value) // Hello
+```
+
+## Type Declarations
+
+```ts
+/**
+ * Holds the previous value of a ref.
+ *
+ * @see   {@link https://vueuse.org/usePrevious}
+ */
+export declare function usePrevious<T>(
+  value: MaybeRefOrGetter<T>,
+): Readonly<ShallowRef<T | undefined>>
+export declare function usePrevious<T>(
+  value: MaybeRefOrGetter<T>,
+  initialValue: T,
+): Readonly<ShallowRef<T>>
+```