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/StaffAssignment.php

@@ -0,0 +1,95 @@
+<?php
+
+namespace App\Models;
+
+use App\Models\Concerns\BelongsToOwner;
+use Carbon\CarbonInterface;
+use Illuminate\Database\Eloquent\Builder;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\SoftDeletes;
+
+class StaffAssignment extends Model
+{
+    use BelongsToOwner, SoftDeletes;
+
+    protected $table = 'care_staff_assignments';
+
+    protected $fillable = [
+        'owner_ref',
+        'organization_id',
+        'member_id',
+        'department_id',
+        'care_unit_id',
+        'kind',
+        'assignment_role',
+        'shift_code',
+        'starts_on',
+        'ends_on',
+        'status',
+        'notes',
+    ];
+
+    protected function casts(): array
+    {
+        return [
+            'starts_on' => 'date',
+            'ends_on' => 'date',
+        ];
+    }
+
+    public function organization(): BelongsTo
+    {
+        return $this->belongsTo(Organization::class, 'organization_id');
+    }
+
+    public function member(): BelongsTo
+    {
+        return $this->belongsTo(Member::class, 'member_id');
+    }
+
+    public function department(): BelongsTo
+    {
+        return $this->belongsTo(Department::class, 'department_id');
+    }
+
+    public function careUnit(): BelongsTo
+    {
+        return $this->belongsTo(CareUnit::class, 'care_unit_id');
+    }
+
+    public function scopeEffectiveOn(Builder $query, CarbonInterface|string|null $date = null): Builder
+    {
+        $day = $date
+            ? (\Illuminate\Support\Carbon::parse($date)->toDateString())
+            : now()->toDateString();
+
+        return $query
+            ->whereDate('starts_on', '<=', $day)
+            ->where(function (Builder $q) use ($day) {
+                $q->whereNull('ends_on')->orWhereDate('ends_on', '>=', $day);
+            });
+    }
+
+    public function scopeActiveStatus(Builder $query): Builder
+    {
+        return $query->where('status', 'active');
+    }
+
+    public function isEffectiveOn(CarbonInterface|string|null $date = null): bool
+    {
+        $day = $date
+            ? \Illuminate\Support\Carbon::parse($date)->startOfDay()
+            : now()->startOfDay();
+
+        if ($this->starts_on->gt($day)) {
+            return false;
+        }
+
+        if ($this->ends_on !== null && $this->ends_on->lt($day)) {
+            return false;
+        }
+
+        return $this->status === 'active';
+    }
+}