feat: M2 database migration runner with Phinx and initial schema

db/migrations/20261011120005_create_thumbnails.php

@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+use Phinx\Migration\AbstractMigration;
+
+/**
+ * Schema: uploaded thumbnails.
+ *
+ * Thumbnails are user-uploaded images associated with models.
+ * They are stored in the managed library under a thumbnails/ subdirectory
+ * and tracked separately from model files.
+ */
+final class CreateThumbnails extends AbstractMigration
+{
+    public function change(): void
+    {
+        $this->table('thumbnails', ['id' => 'id', 'primary_key' => 'id'])
+            ->addColumn('model_id', 'integer', ['null' => false, 'signed' => false])
+            ->addColumn('managed_path', 'text', ['null' => false])
+            ->addColumn('hash', 'string', ['limit' => 64, 'null' => false]) // SHA-256 hex
+            ->addColumn('size', 'biginteger', ['null' => false, 'signed' => false])
+            ->addColumn('mime_type', 'string', ['limit' => 128, 'null' => false])
+            ->addColumn('width', 'integer', ['null' => true, 'signed' => false])
+            ->addColumn('height', 'integer', ['null' => true, 'signed' => false])
+            ->addColumn('uploaded_at', 'timestamp', ['default' => 'CURRENT_TIMESTAMP', 'timezone' => true])
+            ->addForeignKey('model_id', 'models', 'id', ['delete' => 'CASCADE', 'update' => 'NO_ACTION'])
+            ->addIndex(['model_id'], ['name' => 'idx_thumbnails_model_id'])
+            ->addIndex(['hash'], ['unique' => true, 'name' => 'idx_thumbnails_hash'])
+            ->create();
+    }
+}