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/app/(settings)/settings/profile/page.tsx

@@ -239,19 +239,6 @@ export default function ProfileSettingsPage() {
             />
           </div>
 
-          <div className="flex justify-end">
-            <Button
-              onClick={handleSaveProfile}
-              disabled={updateProfile.isPending}
-            >
-              {updateProfile.isPending ? (
-                <Loader2 className="mr-2 h-4 w-4 animate-spin" />
-              ) : (
-                <Save className="mr-2 h-4 w-4" />
-              )}
-              Save Changes
-            </Button>
-          </div>
         </CardContent>
       </Card>
 
@@ -285,19 +272,6 @@ export default function ProfileSettingsPage() {
             </Select>
           </div>
 
-          <div className="flex justify-end">
-            <Button
-              onClick={handleSaveProfile}
-              disabled={updateProfile.isPending}
-            >
-              {updateProfile.isPending ? (
-                <Loader2 className="mr-2 h-4 w-4 animate-spin" />
-              ) : (
-                <Save className="mr-2 h-4 w-4" />
-              )}
-              Save Preferences
-            </Button>
-          </div>
         </CardContent>
       </Card>
 
@@ -320,22 +294,25 @@ export default function ProfileSettingsPage() {
             maxTags={15}
           />
 
-          <div className="flex justify-end">
-            <Button
-              onClick={handleSaveProfile}
-              disabled={updateProfile.isPending}
-            >
-              {updateProfile.isPending ? (
-                <Loader2 className="mr-2 h-4 w-4 animate-spin" />
-              ) : (
-                <Save className="mr-2 h-4 w-4" />
-              )}
-              Save Expertise
-            </Button>
-          </div>
         </CardContent>
       </Card>
 
+      {/* Save All Profile Changes */}
+      <div className="flex justify-end">
+        <Button
+          onClick={handleSaveProfile}
+          disabled={updateProfile.isPending}
+          size="lg"
+        >
+          {updateProfile.isPending ? (
+            <Loader2 className="mr-2 h-4 w-4 animate-spin" />
+          ) : (
+            <Save className="mr-2 h-4 w-4" />
+          )}
+          Save All Changes
+        </Button>
+      </div>
+
       {/* Change Password */}
       <Card>
         <CardHeader>