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/pinia/SKILL.md

@@ -0,0 +1,59 @@
+---
+name: pinia
+description: Pinia official Vue state management library, type-safe and extensible. Use when defining stores, working with state/getters/actions, or implementing store patterns in Vue apps.
+metadata:
+  author: Anthony Fu
+  version: "2026.1.28"
+  source: Generated from https://github.com/vuejs/pinia, scripts located at https://github.com/antfu/skills
+---
+
+# Pinia
+
+Pinia is the official state management library for Vue, designed to be intuitive and type-safe. It supports both Options API and Composition API styles, with first-class TypeScript support and devtools integration.
+
+> The skill is based on Pinia v3.0.4, generated at 2026-01-28.
+
+## Core References
+
+| Topic | Description | Reference |
+|-------|-------------|-----------|
+| Stores | Defining stores, state, getters, actions, storeToRefs, subscriptions | [core-stores](references/core-stores.md) |
+
+## Features
+
+### Extensibility
+
+| Topic | Description | Reference |
+|-------|-------------|-----------|
+| Plugins | Extend stores with custom properties, state, and behavior | [features-plugins](references/features-plugins.md) |
+
+### Composability
+
+| Topic | Description | Reference |
+|-------|-------------|-----------|
+| Composables | Using Vue composables within stores (VueUse, etc.) | [features-composables](references/features-composables.md) |
+| Composing Stores | Store-to-store communication, avoiding circular dependencies | [features-composing-stores](references/features-composing-stores.md) |
+
+## Best Practices
+
+| Topic | Description | Reference |
+|-------|-------------|-----------|
+| Testing | Unit testing with @pinia/testing, mocking, stubbing | [best-practices-testing](references/best-practices-testing.md) |
+| Outside Components | Using stores in navigation guards, plugins, middlewares | [best-practices-outside-component](references/best-practices-outside-component.md) |
+
+## Advanced
+
+| Topic | Description | Reference |
+|-------|-------------|-----------|
+| SSR | Server-side rendering, state hydration | [advanced-ssr](references/advanced-ssr.md) |
+| Nuxt | Nuxt integration, auto-imports, SSR best practices | [advanced-nuxt](references/advanced-nuxt.md) |
+| HMR | Hot module replacement for development | [advanced-hmr](references/advanced-hmr.md) |
+
+## Key Recommendations
+
+- **Prefer Setup Stores** for complex logic, composables, and watchers
+- **Use `storeToRefs()`** when destructuring state/getters to preserve reactivity
+- **Actions can be destructured directly** - they're bound to the store
+- **Call stores inside functions** not at module scope, especially for SSR
+- **Add HMR support** to each store for better development experience
+- **Use `@pinia/testing`** for component tests with mocked stores