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>

src/server/utils/audit.ts

@@ -1,11 +1,19 @@
-import { prisma } from '@/lib/prisma'
-import type { Prisma } from '@prisma/client'
+import { prisma as globalPrisma } from '@/lib/prisma'
+import type { Prisma, PrismaClient } from '@prisma/client'
+
+/** Minimal Prisma-like client that supports auditLog.create (works with PrismaClient and transaction clients). */
+type AuditPrismaClient = Pick<PrismaClient, 'auditLog'>
 
 /**
  * Shared utility for creating audit log entries.
  * Wrapped in try-catch so audit failures never break the calling operation.
+ *
+ * @param input.prisma - Optional Prisma client instance. When omitted the global
+ *   singleton is used. Pass `ctx.prisma` from tRPC handlers so audit writes
+ *   participate in the same transaction when applicable.
  */
 export async function logAudit(input: {
+  prisma?: AuditPrismaClient
   userId?: string | null
   action: string
   entityType: string
@@ -15,7 +23,8 @@ export async function logAudit(input: {
   userAgent?: string
 }): Promise<void> {
   try {
-    await prisma.auditLog.create({
+    const db = input.prisma ?? globalPrisma
+    await db.auditLog.create({
       data: {
         userId: input.userId ?? null,
         action: input.action,