Platform review round 2: audit logging migration, nav unification, DB indexes, and UI polish

- Migrate ~41 inline audit log calls to shared logAudit() utility across all routers
- Add transaction-aware prisma parameter to logAudit() for atomic operations
- Unify jury/mentor/observer navigation into shared RoleNav component
- Add composite DB indexes (Evaluation, GracePeriod, AuditLog) for query performance
- Fix profile page: consolidate dual save buttons, proper useEffect initialization
- Enhance auth error page with MOPC branding and navigation
- Improve observer dashboard with prominent read-only badge
- Fix DI-3: fetch projects before bulk status update for accurate notifications
- Remove unused aiBoost field from smart-assignment scoring
- Add shared image-upload utility and structured logger module

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

prisma/schema.prisma

@@ -250,6 +250,7 @@ model User {
 
   // Award overrides
   awardEligibilityOverrides AwardEligibility[] @relation("AwardEligibilityOverriddenBy")
+  awardWinnerOverrides      SpecialAward[]     @relation("AwardOverriddenBy")
 
   // In-app notifications
   notifications            InAppNotification[] @relation("UserNotifications")
@@ -565,7 +566,9 @@ model Evaluation {
   binaryDecision      Boolean?         // Yes/No for semi-finalist
   feedbackText        String?          @db.Text
 
-  // Versioning
+  // Versioning (currently unused - evaluations are updated in-place.
+  // TODO: Implement proper versioning by creating new rows on re-submission
+  // if version history is needed for audit purposes)
   version             Int              @default(1)
 
   // Timestamps
@@ -580,6 +583,7 @@ model Evaluation {
   @@index([status])
   @@index([submittedAt])
   @@index([formId])
+  @@index([status, formId])
 }
 
 // =============================================================================
@@ -608,6 +612,7 @@ model GracePeriod {
   @@index([extendedUntil])
   @@index([grantedById])
   @@index([projectId])
+  @@index([roundId, userId, extendedUntil])
 }
 
 // =============================================================================
@@ -659,6 +664,7 @@ model AuditLog {
   @@index([action])
   @@index([entityType, entityId])
   @@index([timestamp])
+  @@index([entityType, entityId, timestamp])
 }
 
 // =============================================================================
@@ -1211,7 +1217,7 @@ model SpecialAward {
   // Winner
   winnerProjectId     String?
   winnerOverridden    Boolean          @default(false)
-  winnerOverriddenBy  String?
+  winnerOverriddenBy  String?          // FK to User who overrode the winner
 
   sortOrder        Int              @default(0)
 
@@ -1221,6 +1227,7 @@ model SpecialAward {
   // Relations
   program          Program          @relation(fields: [programId], references: [id], onDelete: Cascade)
   winnerProject    Project?         @relation("AwardWinner", fields: [winnerProjectId], references: [id], onDelete: SetNull)
+  overriddenByUser User?            @relation("AwardOverriddenBy", fields: [winnerOverriddenBy], references: [id], onDelete: SetNull)
   eligibilities    AwardEligibility[]
   jurors           AwardJuror[]
   votes            AwardVote[]