feat(usermanagement): enhance user-branch relationship by syncing branches and adding timestamps

app/Http/Controllers/UsersController.php

@@ -217,11 +217,23 @@ class UsersController extends Controller
 
         if ($validated) {
             $user = User::create($validated);
+
             if ($user) {
                 if ($request->roles) {
                     $user->assignRole($request->roles);
                 }
 
+                $branches = $request->input('branches', []);
+
+                $user->branches()->sync($branches);
+
+                if (!empty($branches)) {
+                    $firstBranchId = $branches[0];
+
+                    $user->branch_id = $firstBranchId;
+                    $user->save();
+                }
+
                 return redirect()->route('users.index')->with('success', 'User created successfully.');
             }
         }

app/Models/User.php

@@ -110,6 +110,7 @@ class User extends Authenticatable
 
     public function branches()
     {
-        return $this->belongsToMany(Branch::class, 'user_branches', 'user_id', 'branch_id');
+        return $this->belongsToMany(Branch::class, 'user_branches', 'user_id', 'branch_id')
+            ->withTimestamps();
     }
 }

app/Models/UserBranch.php

@@ -24,7 +24,8 @@ class UserBranch extends Model
 
     public function user()
     {
-        return $this->belongsTo(User::class);
+        return $this->belongsTo(User::class)
+            ->withTimestamps();
     }
 
     public function branch()