feat: Implement user-branch relationship and update user management views

- Added a many-to-many relationship between users and branches in User model.
- Updated user creation and editing views to support multiple branch selection.
- Modified user index view to display associated branches.
- Created UserBranch model to manage user-branch associations.
- Added migration for user_branches table with foreign key constraints.
- Implemented seeder to populate user_branches based on existing user branch data.

Run this command:
- php artisan migrate
- php artisan module:seed Usermanagement --class=UserBranchesSeeder

database/migrations/2025_12_11_084248_create_user_branches_table.php

@@ -0,0 +1,34 @@
+<?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('user_branches', function (Blueprint $table) {
+            $table->id();
+            $table->unsignedBigInteger('user_id');
+            $table->unsignedBigInteger('branch_id');
+            $table->timestamps();
+
+            $table->foreign('user_id')->references('id')->on('users')->onDelete('cascade');
+            $table->foreign('branch_id')->references('id')->on('branches')->onDelete('cascade');
+
+            $table->unique(['user_id', 'branch_id']);
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::dropIfExists('user_branches');
+    }
+};