Remove dynamic form builder and complete RoundProject→roundId migration

Major cleanup and schema migration:
- Remove unused dynamic form builder system (ApplicationForm, ApplicationFormField, etc.)
- Complete migration from RoundProject junction table to direct Project.roundId
- Add sortOrder and entryNotificationType fields to Round model
- Add country field to User model for mentor matching
- Enhance onboarding with profile photo and country selection steps
- Fix all TypeScript errors related to roundProjects references
- Remove unused libraries (@radix-ui/react-toast, embla-carousel-react, vaul)

Files removed:
- admin/forms/* pages and related components
- admin/onboarding/* pages
- applicationForm.ts and onboarding.ts routers
- Dynamic form builder Prisma models and enums

Schema changes:
- Removed ApplicationForm, ApplicationFormField, OnboardingStep, ApplicationFormSubmission, SubmissionFile models
- Removed FormFieldType and SpecialFieldType enums
- Added Round.sortOrder, Round.entryNotificationType
- Added User.country

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/server/routers/_app.ts

@@ -15,8 +15,6 @@ import { learningResourceRouter } from './learningResource'
 import { partnerRouter } from './partner'
 import { notionImportRouter } from './notion-import'
 import { typeformImportRouter } from './typeform-import'
-import { applicationFormRouter } from './applicationForm'
-import { onboardingRouter } from './onboarding'
 // Phase 2B routers
 import { tagRouter } from './tag'
 import { applicantRouter } from './applicant'
@@ -52,8 +50,6 @@ export const appRouter = router({
   partner: partnerRouter,
   notionImport: notionImportRouter,
   typeformImport: typeformImportRouter,
-  applicationForm: applicationFormRouter,
-  onboarding: onboardingRouter,
   // Phase 2B routers
   tag: tagRouter,
   applicant: applicantRouter,