chore: update document approval workflow and bug fixes

Modules/ApprovalWorkflow/database/migrations/2026_03_24_210001_create_approval_tables.php

@@ -0,0 +1,39 @@
+<?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('approval_chains', function (Blueprint $table) {
+            $table->id();
+            $table->morphs('approvable'); // approvable_type + approvable_id
+            $table->string('type')->default('general'); // e.g., material_request, invoice, purchase_order
+            $table->string('status')->default('pending');
+            $table->text('notes')->nullable();
+            $table->foreignId('initiated_by')->nullable()->constrained('users')->nullOnDelete();
+            $table->timestamp('completed_at')->nullable();
+            $table->timestamps();
+        });
+
+        Schema::create('approval_steps', function (Blueprint $table) {
+            $table->id();
+            $table->foreignId('approval_chain_id')->constrained()->cascadeOnDelete();
+            $table->foreignId('approver_id')->constrained('users')->cascadeOnDelete();
+            $table->integer('order')->default(0);
+            $table->string('status')->default('pending');
+            $table->text('notes')->nullable();
+            $table->timestamp('acted_at')->nullable();
+            $table->timestamps();
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::dropIfExists('approval_steps');
+        Schema::dropIfExists('approval_chains');
+    }
+};

Modules/ApprovalWorkflow/database/seeders/ApprovalWorkflowDatabaseSeeder.php

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+<?php
+
+namespace Modules\ApprovalWorkflow\Database\Seeders;
+
+use Illuminate\Database\Seeder;
+
+class ApprovalWorkflowDatabaseSeeder extends Seeder
+{
+    /**
+     * Run the database seeds.
+     */
+    public function run(): void
+    {
+        // $this->call([]);
+    }
+}