Add Care Units, beds, and dated staff assignments.

Models employment as department/unit/shift placements with primary and temporary kinds so nurses are not permanently bound to a ward.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/Models/Department.php

@@ -5,6 +5,7 @@ namespace App\Models;
 use App\Models\Concerns\BelongsToOwner;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\HasMany;
 use Illuminate\Database\Eloquent\SoftDeletes;
 
 class Department extends Model
@@ -27,6 +28,13 @@ class Department extends Model
         return $this->belongsTo(Branch::class, 'branch_id');
     }
 
+    public function careUnits(): HasMany
+    {
+        return $this->hasMany(CareUnit::class, 'department_id')
+            ->orderBy('sort_order')
+            ->orderBy('name');
+    }
+
     /**
      * Select option label — includes branch when set so multi-branch duplicates are distinguishable.
      */