feat(bundles): add editorial bundle plugins

plugins/antigravity-bundle-full-stack-developer/skills/api-patterns/auth.md

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+# Authentication Patterns
+
+> Choose auth pattern based on use case.
+
+## Selection Guide
+
+| Pattern | Best For |
+|---------|----------|
+| **JWT** | Stateless, microservices |
+| **Session** | Traditional web, simple |
+| **OAuth 2.0** | Third-party integration |
+| **API Keys** | Server-to-server, public APIs |
+| **Passkey** | Modern passwordless (2025+) |
+
+## JWT Principles
+
+```
+Important:
+├── Always verify signature
+├── Check expiration
+├── Include minimal claims
+├── Use short expiry + refresh tokens
+└── Never store sensitive data in JWT
+```