feat: add 33 skills from vudovn/antigravity-kit

- Added: api-patterns, app-builder, architecture, bash-linux, behavioral-modes,
  clean-code, code-review-checklist, database-design, deployment-procedures,
  docker-expert, documentation-templates, game-development, geo-fundamentals,
  i18n-localization, lint-and-validate, mobile-design, nestjs-expert,
  nextjs-best-practices, nodejs-best-practices, parallel-agents,
  performance-profiling, plan-writing, powershell-windows, prisma-expert,
  python-patterns, react-patterns, red-team-tactics, seo-fundamentals,
  server-management, tailwind-patterns, tdd-workflow, typescript-expert,
  vulnerability-scanner
- Updated README: skill count 179 → 223
- Added credit for vudovn/antigravity-kit (MIT License)

Source: https://github.com/vudovn/antigravity-kit

skills/app-builder/templates/nextjs-fullstack/TEMPLATE.md

@@ -0,0 +1,82 @@
+---
+name: nextjs-fullstack
+description: Next.js full-stack template principles. App Router, Prisma, Tailwind.
+---
+
+# Next.js Full-Stack Template
+
+## Tech Stack
+
+| Component | Technology |
+|-----------|------------|
+| Framework | Next.js 14 (App Router) |
+| Language | TypeScript |
+| Database | PostgreSQL + Prisma |
+| Styling | Tailwind CSS |
+| Auth | Clerk (optional) |
+| Validation | Zod |
+
+---
+
+## Directory Structure
+
+```
+project-name/
+├── prisma/
+│   └── schema.prisma
+├── src/
+│   ├── app/
+│   │   ├── layout.tsx
+│   │   ├── page.tsx
+│   │   ├── globals.css
+│   │   └── api/
+│   ├── components/
+│   │   └── ui/
+│   ├── lib/
+│   │   ├── db.ts        # Prisma client
+│   │   └── utils.ts
+│   └── types/
+├── .env.example
+└── package.json
+```
+
+---
+
+## Key Concepts
+
+| Concept | Description |
+|---------|-------------|
+| Server Components | Default, fetch data |
+| Server Actions | Form mutations |
+| Route Handlers | API endpoints |
+| Prisma | Type-safe ORM |
+
+---
+
+## Environment Variables
+
+| Variable | Purpose |
+|----------|---------|
+| DATABASE_URL | Prisma connection |
+| NEXT_PUBLIC_APP_URL | Public URL |
+
+---
+
+## Setup Steps
+
+1. `npx create-next-app {{name}} --typescript --tailwind --app`
+2. `npm install prisma @prisma/client zod`
+3. `npx prisma init`
+4. Configure schema
+5. `npm run db:push`
+6. `npm run dev`
+
+---
+
+## Best Practices
+
+- Server Components by default
+- Server Actions for mutations
+- Prisma for type-safe DB
+- Zod for validation
+- Edge runtime where possible