Competition/Round architecture: full platform rewrite (Phases 1-9)

Replace Pipeline/Stage system with Competition/Round architecture.
New schema: Competition, Round (7 types), JuryGroup, AssignmentPolicy,
ProjectRoundState, DeliberationSession, ResultLock, SubmissionWindow.
New services: round-engine, round-assignment, deliberation, result-lock,
submission-manager, competition-context, ai-prompt-guard.
Full admin/jury/applicant/mentor UI rewrite. AI prompt hardening with
structured prompts, retry logic, and injection detection. All legacy
pipeline/stage code removed. 4 new migrations + seed aligned.

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

src/components/layouts/applicant-nav.tsx

@@ -20,8 +20,8 @@ export function ApplicantNav({ user }: ApplicantNavProps) {
       icon: Users,
     },
     {
-      name: 'Pipeline',
-      href: '/applicant/pipeline',
+      name: 'Competitions',
+      href: '/applicant/competitions',
       icon: Layers,
     },
     {