fix tables to have school year, and remove school year from other tables.

app/Models/Student.php

@@ -99,7 +99,12 @@ class Student extends BaseModel
             return $q;
         }
 
-        return $q->where('school_year', $schoolYear);
+        return $q->whereExists(function ($sub) use ($schoolYear) {
+            $sub->selectRaw('1')
+                ->from('student_class as sc')
+                ->whereColumn('sc.student_id', 'students.id')
+                ->where('sc.school_year', $schoolYear);
+        });
     }
 
     public function scopeOrderByName(Builder $q): Builder
@@ -197,9 +202,14 @@ class Student extends BaseModel
             $q->whereIn('students.is_new', [0, 1]);
         }
 
-        // school_year filter (skip if null or "all")
+        // Students are global identities; year rosters come from yearly class/enrollment rows.
         if ($schoolYear !== null && strtolower($schoolYear) !== 'all') {
-            $q->where('students.school_year', $schoolYear);
+            $q->whereExists(function ($sub) use ($schoolYear) {
+                $sub->selectRaw('1')
+                    ->from('student_class as sc')
+                    ->whereColumn('sc.student_id', 'students.id')
+                    ->where('sc.school_year', $schoolYear);
+            });
         }
 
         return $q->groupBy('students.id')