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/vue-best-practices/reference/computed-no-side-effects.md

@@ -0,0 +1,107 @@
+---
+title: Computed Property Getters Must Be Side-Effect Free
+impact: HIGH
+impactDescription: Side effects in computed getters break reactivity and cause unpredictable behavior
+type: efficiency
+tags: [vue3, computed, reactivity, side-effects, best-practices]
+---
+
+# Computed Property Getters Must Be Side-Effect Free
+
+**Impact: HIGH** - Computed getter functions should only perform pure computation. Side effects in computed getters break Vue's reactivity model and cause bugs that are difficult to trace.
+
+Computed properties are designed to declaratively describe how to derive a value from other reactive state. They are not meant to perform actions or modify state.
+
+## Task Checklist
+
+- [ ] Never mutate other reactive state inside a computed getter
+- [ ] Never make async requests or API calls inside a computed getter
+- [ ] Never perform DOM mutations inside a computed getter
+- [ ] Use watchers for reacting to state changes with side effects
+- [ ] Use event handlers for user-triggered actions
+
+**Incorrect:**
+```vue
+<script setup>
+import { ref, computed } from 'vue'
+
+const items = ref([])
+const count = ref(0)
+const lastFetch = ref(null)
+
+// BAD: Mutates other state
+const doubledCount = computed(() => {
+  count.value++  // Side effect - modifying state!
+  return count.value * 2
+})
+
+// BAD: Makes async request
+const userData = computed(async () => {
+  const response = await fetch('/api/user')  // Side effect - API call!
+  return response.json()
+})
+
+// BAD: Modifies DOM
+const highlightedItems = computed(() => {
+  document.title = `${items.value.length} items`  // Side effect - DOM mutation!
+  return items.value.filter(i => i.highlighted)
+})
+
+// BAD: Writes to external state
+const processedData = computed(() => {
+  lastFetch.value = new Date()  // Side effect - modifying state!
+  return items.value.map(i => i.name)
+})
+</script>
+```
+
+**Correct:**
+```vue
+<script setup>
+import { ref, computed, watch, onMounted } from 'vue'
+
+const items = ref([])
+const count = ref(0)
+const userData = ref(null)
+
+// GOOD: Pure computation only
+const doubledCount = computed(() => {
+  return count.value * 2
+})
+
+// GOOD: Use lifecycle hook for initial fetch
+onMounted(async () => {
+  const response = await fetch('/api/user')
+  userData.value = await response.json()
+})
+
+// GOOD: Pure filtering
+const highlightedItems = computed(() => {
+  return items.value.filter(i => i.highlighted)
+})
+
+// GOOD: Use watcher for side effects
+watch(items, (newItems) => {
+  document.title = `${newItems.length} items`
+}, { immediate: true })
+
+// Increment count through event handler, not computed
+function increment() {
+  count.value++
+}
+</script>
+```
+
+## What Counts as a Side Effect
+
+| Side Effect Type | Example | Alternative |
+|-----------------|---------|-------------|
+| State mutation | `otherRef.value = x` | Use watcher |
+| API calls | `fetch()`, `axios()` | Use watcher or lifecycle hook |
+| DOM manipulation | `document.title = x` | Use watcher |
+| Console logging | `console.log()` | Remove or use watcher |
+| Storage access | `localStorage.setItem()` | Use watcher |
+| Timer setup | `setTimeout()` | Use lifecycle hook |
+
+## Reference
+- [Vue.js Computed Properties - Getters Should Be Side-Effect Free](https://vuejs.org/guide/essentials/computed.html#getters-should-be-side-effect-free)