Initial commit: CABM-IT (ItGlue-style MSP documentation platform)

Laravel 13 + Livewire/Volt app for managing client organizations,
documents, passwords, flexible assets, virtual machines, contacts,
domains, todos, shortcuts, and role-based user administration.

app/Models/RelatedItem.php

@@ -0,0 +1,48 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\MorphTo;
+
+class RelatedItem extends Model
+{
+    protected $guarded = [];
+
+    public function item(): MorphTo
+    {
+        return $this->morphTo(__FUNCTION__, 'item_type', 'item_id');
+    }
+
+    public function relatedItem(): MorphTo
+    {
+        return $this->morphTo(__FUNCTION__, 'related_item_type', 'related_item_id');
+    }
+
+    public function creator()
+    {
+        return $this->belongsTo(User::class, 'created_by');
+    }
+
+    /**
+     * All edges touching a given model, either as owner or as target (symmetric view).
+     */
+    public static function forItem(Model $model)
+    {
+        return static::where(function ($query) use ($model) {
+            $query->where('item_type', $model->getMorphClass())->where('item_id', $model->getKey());
+        })->orWhere(function ($query) use ($model) {
+            $query->where('related_item_type', $model->getMorphClass())->where('related_item_id', $model->getKey());
+        });
+    }
+
+    /**
+     * The model on the "other side" of this edge, relative to the given model.
+     */
+    public function otherItem(Model $relativeTo): ?Model
+    {
+        $isOwner = $this->item_type === $relativeTo->getMorphClass() && (string) $this->item_id === (string) $relativeTo->getKey();
+
+        return $isOwner ? $this->relatedItem : $this->item;
+    }
+}