Rename company-scoped Users to Members throughout

Complete rename across backend and frontend:
- Controller: Company/Users/UsersController -> Company/Members/MembersController
- Service: UserService -> MemberService
- Requests: UserRequest -> MemberRequest, DeleteUserRequest -> DeleteMemberRequest
- API routes: /api/v1/users -> /api/v1/members (company-scoped only)
- Sidebar menu: "Users" -> "Members"
- Frontend: views/users -> views/members, stores/users -> stores/members
- Router: users.index -> members.index, /admin/users -> /admin/members
- i18n: new "members" section with invitation-related keys
- Tests: UserTest -> MemberTest

Admin/super-admin Users (system-wide user management) remains unchanged.

app/Services/MemberService.php

@@ -0,0 +1,90 @@
+<?php
+
+namespace App\Services;
+
+use App\Http\Requests\MemberRequest;
+use App\Models\CompanySetting;
+use App\Models\User;
+use Silber\Bouncer\BouncerFacade;
+
+class MemberService
+{
+    public function create(MemberRequest $request): User
+    {
+        $user = User::create($request->getUserPayload());
+
+        $user->setSettings([
+            'language' => CompanySetting::getSetting('language', $request->header('company')),
+        ]);
+
+        $companies = collect($request->companies);
+        $user->companies()->sync($companies->pluck('id'));
+
+        foreach ($companies as $company) {
+            BouncerFacade::scope()->to($company['id']);
+
+            BouncerFacade::sync($user)->roles([$company['role']]);
+        }
+
+        return $user;
+    }
+
+    public function update(User $user, MemberRequest $request): User
+    {
+        $user->update($request->getUserPayload());
+
+        $companies = collect($request->companies);
+        $user->companies()->sync($companies->pluck('id'));
+
+        foreach ($companies as $company) {
+            BouncerFacade::scope()->to($company['id']);
+
+            BouncerFacade::sync($user)->roles([$company['role']]);
+        }
+
+        return $user;
+    }
+
+    public function delete(array $ids): bool
+    {
+        foreach ($ids as $id) {
+            $user = User::find($id);
+
+            if ($user->invoices()->exists()) {
+                $user->invoices()->update(['creator_id' => null]);
+            }
+
+            if ($user->estimates()->exists()) {
+                $user->estimates()->update(['creator_id' => null]);
+            }
+
+            if ($user->customers()->exists()) {
+                $user->customers()->update(['creator_id' => null]);
+            }
+
+            if ($user->recurringInvoices()->exists()) {
+                $user->recurringInvoices()->update(['creator_id' => null]);
+            }
+
+            if ($user->expenses()->exists()) {
+                $user->expenses()->update(['creator_id' => null]);
+            }
+
+            if ($user->payments()->exists()) {
+                $user->payments()->update(['creator_id' => null]);
+            }
+
+            if ($user->items()->exists()) {
+                $user->items()->update(['creator_id' => null]);
+            }
+
+            if ($user->settings()->exists()) {
+                $user->settings()->delete();
+            }
+
+            $user->delete();
+        }
+
+        return true;
+    }
+}