refactor(onboarding): restructure onboarding routes and components

- Removed obsolete onboarding routes: complete, create-complex, index, verify-email, and verify.
- Introduced new setup stepper page for onboarding process.
- Created a multi-step setup component to handle complex creation with validation.
- Added new schemas for complex creation and plan features.
- Implemented detailed steps for complex name, location, plan selection, and court setup.
- Enhanced error handling and user feedback during the onboarding process.

apps/backend/prisma/onboarding.prisma

@@ -1,18 +0,0 @@
-model OnboardingRequest {
-  id            String    @id @db.Uuid
-  fullName      String    @map("full_name")
-  email         String
-  otpHash       String    @map("otp_hash")
-  otpExpiresAt  DateTime  @map("otp_expires_at")
-  otpAttempts   Int       @default(0) @map("otp_attempts")
-  otpLastSentAt DateTime  @map("otp_last_sent_at")
-  otpResendCount Int      @default(0) @map("otp_resend_count")
-  emailVerifiedAt DateTime? @map("email_verified_at")
-  completedAt     DateTime? @map("completed_at")
-  createdAt       DateTime  @default(now()) @map("created_at")
-  updatedAt       DateTime  @updatedAt @map("updated_at")
-
-  @@index([email])
-  @@index([otpExpiresAt])
-  @@map("onboarding_requests")
-}