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/api-patterns/rest.md

@@ -0,0 +1,40 @@
+# REST Principles
+
+> Resource-based API design - nouns not verbs.
+
+## Resource Naming Rules
+
+```
+Principles:
+├── Use NOUNS, not verbs (resources, not actions)
+├── Use PLURAL forms (/users not /user)
+├── Use lowercase with hyphens (/user-profiles)
+├── Nest for relationships (/users/123/posts)
+└── Keep shallow (max 3 levels deep)
+```
+
+## HTTP Method Selection
+
+| Method | Purpose | Idempotent? | Body? |
+|--------|---------|-------------|-------|
+| **GET** | Read resource(s) | Yes | No |
+| **POST** | Create new resource | No | Yes |
+| **PUT** | Replace entire resource | Yes | Yes |
+| **PATCH** | Partial update | No | Yes |
+| **DELETE** | Remove resource | Yes | No |
+
+## Status Code Selection
+
+| Situation | Code | Why |
+|-----------|------|-----|
+| Success (read) | 200 | Standard success |
+| Created | 201 | New resource created |
+| No content | 204 | Success, nothing to return |
+| Bad request | 400 | Malformed request |
+| Unauthorized | 401 | Missing/invalid auth |
+| Forbidden | 403 | Valid auth, no permission |
+| Not found | 404 | Resource doesn't exist |
+| Conflict | 409 | State conflict (duplicate) |
+| Validation error | 422 | Valid syntax, invalid data |
+| Rate limited | 429 | Too many requests |
+| Server error | 500 | Our fault |