feat: tambah sistem poin anggota (kehadiran +10, artikel +5)

- Model MemberPoint + migration
- PostObserver: +5 poin saat artikel dipublish
- ActivityObserver: +10 poin saat peserta hadir di kegiatan
- MemberPointResource: tampil di grup Organisasi
- MemberPointSeeder + update ActivitySeeder dengan pivot status kehadiran
- Update PermissionSeeder: anggota bisa lihat poin

app/Models/MemberPoint.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+class MemberPoint extends Model
+{
+    protected $fillable = ['user_id', 'points', 'reason', 'source_type', 'source_id'];
+
+    public function user(): BelongsTo
+    {
+        return $this->belongsTo(User::class);
+    }
+}