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/app/(admin)/admin/projects/[id]/mentor/page.tsx

@@ -160,7 +160,7 @@ function MentorAssignmentContent({ projectId }: { projectId: string }) {
                   <p className="text-sm text-muted-foreground">{project.mentorAssignment!.mentor.email}</p>
                   {project.mentorAssignment!.mentor.expertiseTags && project.mentorAssignment!.mentor.expertiseTags.length > 0 && (
                     <div className="flex flex-wrap gap-1 mt-1">
-                      {project.mentorAssignment!.mentor.expertiseTags.slice(0, 3).map((tag) => (
+                      {project.mentorAssignment!.mentor.expertiseTags.slice(0, 3).map((tag: string) => (
                         <Badge key={tag} variant="secondary" className="text-xs">{tag}</Badge>
                       ))}
                     </div>