feat: [rd] CM송 저장 테이블 마이그레이션 추가

- cm_songs 테이블: tenant_id, user_id, company_name, industry, lyrics, audio_path, options

database/migrations/2026_03_05_170000_create_cm_songs_table.php

@@ -0,0 +1,29 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    public function up(): void
+    {
+        Schema::create('cm_songs', function (Blueprint $table) {
+            $table->id();
+            $table->unsignedBigInteger('tenant_id')->index();
+            $table->unsignedBigInteger('user_id')->index();
+            $table->string('company_name', 100);
+            $table->string('industry', 200);
+            $table->text('lyrics');
+            $table->string('audio_path')->nullable();
+            $table->json('options')->nullable();
+            $table->timestamps();
+            $table->softDeletes();
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::dropIfExists('cm_songs');
+    }
+};