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/slot-fallback-content-default-values.md

@@ -0,0 +1,135 @@
+---
+title: Provide Fallback Content for Slots
+impact: LOW
+impactDescription: Components without slot fallbacks may render empty or broken when content is not provided
+type: best-practice
+tags: [vue3, slots, fallback-content, component-design, reusability]
+---
+
+# Provide Fallback Content for Slots
+
+**Impact: LOW** - Providing sensible default content inside `<slot>` elements makes components more resilient and user-friendly. Fallback content renders when no slot content is provided by the parent.
+
+## Task Checklist
+
+- [ ] Add fallback content inside slot elements for optional slots
+- [ ] Use meaningful defaults that make sense standalone
+- [ ] Consider i18n for text fallbacks in internationalized apps
+- [ ] Document which slots have fallbacks and what they display
+
+**Without Fallback (fragile):**
+```vue
+<!-- SubmitButton.vue -->
+<template>
+  <button type="submit" class="btn-primary">
+    <!-- Empty if no content provided -->
+    <slot></slot>
+  </button>
+</template>
+```
+
+```vue
+<!-- Usage without content - renders empty button -->
+<SubmitButton />
+<!-- Result: <button type="submit" class="btn-primary"></button> -->
+```
+
+**With Fallback (resilient):**
+```vue
+<!-- SubmitButton.vue -->
+<template>
+  <button type="submit" class="btn-primary">
+    <slot>Submit</slot>
+  </button>
+</template>
+```
+
+```vue
+<!-- Usage without content - shows default -->
+<SubmitButton />
+<!-- Result: <button type="submit" class="btn-primary">Submit</button> -->
+
+<!-- Usage with content - overrides default -->
+<SubmitButton>Save Changes</SubmitButton>
+<!-- Result: <button type="submit" class="btn-primary">Save Changes</button> -->
+```
+
+## Named Slots with Fallbacks
+
+```vue
+<!-- Card.vue -->
+<template>
+  <div class="card">
+    <header class="card-header">
+      <slot name="header">
+        <h3>Card Title</h3>
+      </slot>
+    </header>
+
+    <main class="card-body">
+      <slot>
+        <p>No content provided.</p>
+      </slot>
+    </main>
+
+    <footer class="card-footer">
+      <slot name="footer">
+        <button>Close</button>
+      </slot>
+    </footer>
+  </div>
+</template>
+```
+
+## Complex Fallback Content
+
+Fallback content can include multiple elements and logic:
+
+```vue
+<!-- UserAvatar.vue -->
+<template>
+  <div class="avatar-container">
+    <slot name="image">
+      <!-- Complex fallback with conditional logic -->
+      <img
+        v-if="user?.avatar"
+        :src="user.avatar"
+        :alt="user.name"
+      />
+      <div v-else class="avatar-placeholder">
+        {{ initials }}
+      </div>
+    </slot>
+  </div>
+</template>
+
+<script setup>
+import { computed } from 'vue'
+
+const props = defineProps({
+  user: Object
+})
+
+const initials = computed(() => {
+  if (!props.user?.name) return '?'
+  return props.user.name
+    .split(' ')
+    .map(n => n[0])
+    .join('')
+    .toUpperCase()
+})
+</script>
+```
+
+## When to Use Fallbacks
+
+| Slot Purpose | Fallback Recommended? | Example |
+|--------------|----------------------|---------|
+| Button text | Yes | "Submit", "Click here" |
+| Icon slot | Yes | Default icon component |
+| Modal title | Yes | "Dialog" |
+| Required content area | No | Main content slot |
+| Customization only | Optional | Action buttons slot |
+
+## Reference
+- [Vue.js Slots - Fallback Content](https://vuejs.org/guide/components/slots.html#fallback-content)