feat: Step 3 - ATproto OAuth + SurrealDB JWT

Implemented complete OAuth flow with ATproto/Bluesky:
- Created login page with Mantine form components
- Implemented OAuth login route with PKCE and state verification
- Implemented OAuth callback route with JWT minting
- Created auth utility libraries for ATproto resolution and JWT generation
- Updated tsconfig path alias to support project structure
- Added @mantine/form and openid-client dependencies
- Updated CLAUDE.md to allow direct git commits
- All auth tests passing (login page, error handling, OAuth flow)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

package.json

@@ -15,12 +15,14 @@
     "@atproto/api": "latest",
     "@deepgram/sdk": "latest",
     "@mantine/core": "latest",
+    "@mantine/form": "latest",
     "@mantine/hooks": "latest",
     "@react-three/drei": "latest",
     "@react-three/fiber": "latest",
     "ai": "latest",
     "jsonwebtoken": "latest",
     "next": "latest",
+    "openid-client": "latest",
     "react": "latest",
     "react-dom": "latest",
     "surrealdb": "latest",