Adds authentication and pricing pages for user onboarding

Introduces comprehensive user authentication flow with plan selection and registration

Includes:
- Pricing page with plan details and selection
- Payment page with plan summary and card information
- Signup page for different plan tiers
- Shared authentication layout and design system improvements

Enhances user onboarding experience with clear plan information and streamlined signup process

.claude/settings.local.json

@@ -3,7 +3,8 @@
     "allow": [
       "Bash(cd:*)",
       "Bash(ls:*)",
-      "Bash(dotnet build:*)"
+      "Bash(dotnet build:*)",
+      "Bash(find:*)"
     ]
   }
 }