feat(01-01): add Member notes relationship, morph map, and NoteFactory

- Add notes() morphMany relationship to Member model (ordered by created_at desc)
- Register morph map in AppServiceProvider ('member' => Member::class)
- Create NoteFactory with forMember() and byAuthor() state methods

app/Models/Member.php

@@ -4,6 +4,7 @@ namespace App\Models;
 
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\MorphMany;
 use Illuminate\Support\Facades\Crypt;
 
 class Member extends Model
@@ -110,6 +111,14 @@ class Member extends Model
         return $this->hasMany(Member::class, 'guardian_member_id');
     }
 
+    /**
+     * 會員備註（管理員可對任一會員新增備註）
+     */
+    public function notes(): MorphMany
+    {
+        return $this->morphMany(Note::class, 'notable')->orderBy('created_at', 'desc');
+    }
+
     /**
      * 是否為病友
      */

app/Providers/AppServiceProvider.php

@@ -3,7 +3,9 @@
 namespace App\Providers;
 
 use App\Models\Document;
+use App\Models\Member;
 use App\Observers\DocumentObserver;
+use Illuminate\Database\Eloquent\Relations\Relation;
 use Illuminate\Support\ServiceProvider;
 
 class AppServiceProvider extends ServiceProvider
@@ -21,6 +23,11 @@ class AppServiceProvider extends ServiceProvider
      */
     public function boot(): void
     {
+        // Register morph map to protect against namespace refactoring
+        Relation::enforceMorphMap([
+            'member' => Member::class,
+        ]);
+
         Document::observe(DocumentObserver::class);
     }
 }

database/factories/NoteFactory.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace Database\Factories;
+
+use App\Models\Member;
+use App\Models\Note;
+use App\Models\User;
+use Illuminate\Database\Eloquent\Factories\Factory;
+
+class NoteFactory extends Factory
+{
+    protected $model = Note::class;
+
+    public function definition(): array
+    {
+        return [
+            'notable_type' => 'member', // Uses morph map alias
+            'notable_id' => Member::factory(),
+            'content' => $this->faker->paragraph(),
+            'author_user_id' => User::factory(),
+        ];
+    }
+
+    /**
+     * Set the note to belong to a specific member
+     */
+    public function forMember(Member $member): static
+    {
+        return $this->state(fn () => [
+            'notable_type' => 'member',
+            'notable_id' => $member->id,
+        ]);
+    }
+
+    /**
+     * Set the note to be authored by a specific user
+     */
+    public function byAuthor(User $user): static
+    {
+        return $this->state(fn () => [
+            'author_user_id' => $user->id,
+        ]);
+    }
+}