Improve projects UX, settings layout, uppercase names, per-page selector, and fix round deletion

- Fix round deletion FK constraint: add onDelete Cascade on Evaluation.form and SetNull on ProjectFile.round
- Add configurable per-page selector (10/20/50/100) to Pagination component, wired in projects page with URL sync
- Add display_project_names_uppercase setting in admin defaults, applied to project titles across desktop/mobile views
- Redesign admin settings page: vertical sidebar nav on desktop with grouped sections, horizontal scrollable tabs on mobile
- Polish projects page: responsive header with total count, search clear button with result count, status stats bar, submission date column, country display, mobile card file count

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

prisma/schema.prisma

@@ -628,7 +628,7 @@ model ProjectFile {
 
   // Relations
   project     Project          @relation(fields: [projectId], references: [id], onDelete: Cascade)
-  round       Round?           @relation(fields: [roundId], references: [id])
+  round       Round?           @relation(fields: [roundId], references: [id], onDelete: SetNull)
   requirement FileRequirement? @relation(fields: [requirementId], references: [id], onDelete: SetNull)
   replacedBy  ProjectFile?     @relation("FileVersions", fields: [replacedById], references: [id], onDelete: SetNull)
   replacements ProjectFile[]   @relation("FileVersions")
@@ -706,7 +706,7 @@ model Evaluation {
 
   // Relations
   assignment Assignment     @relation(fields: [assignmentId], references: [id], onDelete: Cascade)
-  form       EvaluationForm @relation(fields: [formId], references: [id])
+  form       EvaluationForm @relation(fields: [formId], references: [id], onDelete: Cascade)
 
   @@index([status])
   @@index([submittedAt])