Add per-round assignment constraints (min/max per judge)

- Add minAssignmentsPerJuror and maxAssignmentsPerJuror fields to Round model
- Update assignment router:
  - Calculate effective max from user override or round default
  - Add forceOverride parameter for manual assignment beyond limits
  - Update getSuggestions to use round constraints with min target bonus
  - Update getAISuggestions to pass constraints to AI service
- Update AI assignment service:
  - Add minAssignmentsPerJuror to constraints interface
  - Update fallback algorithm with under-min bonus scoring
  - New score weights: 50% expertise, 30% load, 20% under-min bonus
- Update round router:
  - Add new constraint fields to create/update schemas
  - Add validation for min <= max constraint
- Update admin UI:
  - Add min/max constraint fields to round edit page
  - Remove hardcoded maxPerJuror from assignments page
- Add migration files for production deployment:
  - User.bio field for judge/mentor profiles
  - Round assignment constraint fields

Constraint hierarchy:
1. User.maxAssignments (if set) overrides round default
2. Round.maxAssignmentsPerJuror is the default cap
3. Admin can force-override any limit with confirmation

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

prisma/migrations/20260204140000_add_user_bio/migration.sql

@@ -0,0 +1,3 @@
+-- Add bio field to User model for judge/mentor profile descriptions
+ALTER TABLE "User" ADD COLUMN IF NOT EXISTS "bio" TEXT;
+

prisma/migrations/20260204150000_add_assignment_constraints/migration.sql

@@ -0,0 +1,4 @@
+-- Add assignment constraint fields to Round model
+ALTER TABLE "Round" ADD COLUMN IF NOT EXISTS "minAssignmentsPerJuror" INTEGER NOT NULL DEFAULT 5;
+ALTER TABLE "Round" ADD COLUMN IF NOT EXISTS "maxAssignmentsPerJuror" INTEGER NOT NULL DEFAULT 20;
+

prisma/schema.prisma

@@ -356,8 +356,10 @@ model Round {
   votingEndAt     DateTime?
 
   // Configuration
-  requiredReviews Int         @default(3) // Min evaluations per project
-  settingsJson    Json?       @db.JsonB   // Grace periods, visibility rules, etc.
+  requiredReviews          Int   @default(3)  // Min evaluations per project
+  minAssignmentsPerJuror   Int   @default(5)  // Target minimum projects per judge
+  maxAssignmentsPerJuror   Int   @default(20) // Max projects per judge in this round
+  settingsJson             Json? @db.JsonB    // Grace periods, visibility rules, etc.
 
   createdAt DateTime @default(now())
   updatedAt DateTime @updatedAt