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/(observer)/observer/page.tsx

@@ -48,7 +48,7 @@ async function ObserverDashboardContent() {
         program: { select: { name: true, year: true } },
         _count: {
           select: {
-            roundProjects: true,
+            projects: true,
             assignments: true,
           },
         },
@@ -176,7 +176,7 @@ async function ObserverDashboardContent() {
                     </p>
                   </div>
                   <div className="text-right text-sm">
-                    <p>{round._count.roundProjects} projects</p>
+                    <p>{round._count.projects} projects</p>
                     <p className="text-muted-foreground">
                       {round._count.assignments} assignments
                     </p>