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]/page.tsx

@@ -140,18 +140,13 @@ function ProjectDetailContent({ projectId }: { projectId: string }) {
           />
           <div className="space-y-1">
             <div className="flex flex-wrap items-center gap-1 text-sm text-muted-foreground">
-              {project.roundProjects?.length > 0 ? (
-                project.roundProjects.map((rp, i) => (
-                  <span key={rp.round.id} className="flex items-center gap-1">
-                    {i > 0 && <span className="text-muted-foreground/50">/</span>}
-                    <Link
-                      href={`/admin/rounds/${rp.round.id}`}
-                      className="hover:underline"
-                    >
-                      {rp.round.name}
-                    </Link>
-                  </span>
-                ))
+              {project.roundId ? (
+                <Link
+                  href={`/admin/rounds/${project.roundId}`}
+                  className="hover:underline"
+                >
+                  {project.round?.name ?? 'Round'}
+                </Link>
               ) : (
                 <span>No round</span>
               )}
@@ -160,8 +155,8 @@ function ProjectDetailContent({ projectId }: { projectId: string }) {
               <h1 className="text-2xl font-semibold tracking-tight">
                 {project.title}
               </h1>
-              <Badge variant={statusColors[project.roundProjects?.[0]?.status ?? 'SUBMITTED'] || 'secondary'}>
-                {(project.roundProjects?.[0]?.status ?? 'SUBMITTED').replace('_', ' ')}
+              <Badge variant={statusColors[project.status ?? 'SUBMITTED'] || 'secondary'}>
+                {(project.status ?? 'SUBMITTED').replace('_', ' ')}
               </Badge>
             </div>
             {project.teamName && (
@@ -513,7 +508,7 @@ function ProjectDetailContent({ projectId }: { projectId: string }) {
                 </CardDescription>
               </div>
               <Button variant="outline" size="sm" asChild>
-                <Link href={`/admin/rounds/${project.roundProjects?.[0]?.round?.id}/assignments`}>
+                <Link href={`/admin/rounds/${project.roundId}/assignments`}>
                   Manage
                 </Link>
               </Button>