feat(integration): 實作並測試 POS 與販賣機訂單同步 API

主要變更：
- 實作 POS 與販賣機訂單同步邏輯，支援多租戶與 Sanctum 驗證。
- 修正多租戶識別中間件與 Sanctum 驗證順序問題。
- 切換快取驅動至 Redis 以支援 Tenancy 標籤功能。
- 新增商品同步 API (Upsert) 及相關單元測試。
- 新增手動測試腳本 tests/manual/test_integration_api.sh。
- 前端新增銷售訂單來源篩選與欄位顯示。

database/migrations/2026_02_23_120000_create_notifications_table.php

@@ -0,0 +1,31 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::create('notifications', function (Blueprint $table) {
+            $table->uuid('id')->primary();
+            $table->string('type');
+            $table->morphs('notifiable');
+            $table->text('data');
+            $table->timestamp('read_at')->nullable();
+            $table->timestamps();
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::dropIfExists('notifications');
+    }
+};

database/migrations/tenant/2026_02_23_114909_add_source_to_sales_orders.php

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+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * 為 sales_orders 新增來源標記欄位，支援多來源 API 寫入
+     */
+    public function up(): void
+    {
+        Schema::table('sales_orders', function (Blueprint $table) {
+            $table->string('source')->default('pos')->after('raw_payload');
+            $table->string('source_label')->nullable()->after('source');
+            $table->index('source');
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::table('sales_orders', function (Blueprint $table) {
+            $table->dropIndex(['source']);
+            $table->dropColumn(['source', 'source_label']);
+        });
+    }
+};