feat: Expand fleet to 23 skills across all domains

New skills (14):
- nestjs-best-practices: 40 priority-ranked rules (kadajett)
- fastapi: Pydantic v2, async SQLAlchemy, JWT auth (jezweb)
- architecture-patterns: Clean Architecture, Hexagonal, DDD (wshobson)
- python-performance-optimization: Profiling and optimization (wshobson)
- ai-sdk: Vercel AI SDK streaming and agent patterns (vercel)
- create-agent: Modular agent architecture with OpenRouter (openrouterteam)
- proactive-agent: WAL Protocol, compaction recovery, self-improvement (halthelobster)
- brand-guidelines: Brand identity enforcement (anthropics)
- ui-animation: Motion design with accessibility (mblode)
- marketing-ideas: 139 ideas across 14 categories (coreyhaines31)
- pricing-strategy: SaaS pricing and tier design (coreyhaines31)
- programmatic-seo: SEO at scale with playbooks (coreyhaines31)
- competitor-alternatives: Comparison page architecture (coreyhaines31)
- referral-program: Referral and affiliate programs (coreyhaines31)

README reorganized by domain: Code Quality, Frontend, Backend,
Auth, AI/Agent Building, Marketing, Design, Meta.

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

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

skills/fastapi/.claude-plugin/plugin.json

@@ -0,0 +1,12 @@
+{
+  "name": "fastapi",
+  "description": "Optional[str] # Still required!",
+  "version": "1.0.0",
+  "author": {
+    "name": "Jeremy Dawes",
+    "email": "jeremy@jezweb.net"
+  },
+  "license": "MIT",
+  "repository": "https://github.com/jezweb/claude-skills",
+  "keywords": []
+}