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/architecture/context-discovery.md

@@ -0,0 +1,43 @@
+# Context Discovery
+
+> Before suggesting any architecture, gather context.
+
+## Question Hierarchy (Ask User FIRST)
+
+1. **Scale**
+   - How many users? (10, 1K, 100K, 1M+)
+   - Data volume? (MB, GB, TB)
+   - Transaction rate? (per second/minute)
+
+2. **Team**
+   - Solo developer or team?
+   - Team size and expertise?
+   - Distributed or co-located?
+
+3. **Timeline**
+   - MVP/Prototype or long-term product?
+   - Time to market pressure?
+
+4. **Domain**
+   - CRUD-heavy or business logic complex?
+   - Real-time requirements?
+   - Compliance/regulations?
+
+5. **Constraints**
+   - Budget limitations?
+   - Legacy systems to integrate?
+   - Technology stack preferences?
+
+## Project Classification Matrix
+
+```
+                    MVP              SaaS           Enterprise
+┌─────────────────────────────────────────────────────────────┐
+│ Scale        │ <1K           │ 1K-100K      │ 100K+        │
+│ Team         │ Solo          │ 2-10         │ 10+          │
+│ Timeline     │ Fast (weeks)  │ Medium (months)│ Long (years)│
+│ Architecture │ Simple        │ Modular      │ Distributed  │
+│ Patterns     │ Minimal       │ Selective    │ Comprehensive│
+│ Example      │ Next.js API   │ NestJS       │ Microservices│
+└─────────────────────────────────────────────────────────────┘
+```