feat: integrate PHPStan, Rector and Pint code quality tools (#13)

* feat: integrate PHPStan, Rector and Pint code quality tools

- Add larastan, rector, and rector-laravel dev dependencies
- Configure PHPStan at max level with Larastan extension
- Configure Rector with Laravel sets and code quality rules
- Configure Pint with strict rules (final_class, strict_types)
- Add composer scripts: lint, test:lint, test:types, test:unit
- Add GitHub Actions workflow for CI on push/PR
- Apply code style fixes across all files

* docs: add code quality section to README

database/factories/UserFactory.php

@@ -1,20 +1,23 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Database\Factories;
 
+use App\Models\User;
 use Illuminate\Database\Eloquent\Factories\Factory;
 use Illuminate\Support\Facades\Hash;
 use Illuminate\Support\Str;
 
 /**
- * @extends \Illuminate\Database\Eloquent\Factories\Factory<\App\Models\User>
+ * @extends Factory<User>
  */
-class UserFactory extends Factory
+final class UserFactory extends Factory
 {
     /**
      * The current password being used by the factory.
      */
-    protected static ?string $password;
+    private static ?string $password = null;
 
     /**
      * Define the model's default state.
@@ -27,7 +30,7 @@ class UserFactory extends Factory
             'name' => fake()->name(),
             'email' => fake()->unique()->safeEmail(),
             'email_verified_at' => now(),
-            'password' => static::$password ??= Hash::make('password'),
+            'password' => self::$password ??= Hash::make('password'),
             'remember_token' => Str::random(10),
         ];
     }
@@ -37,7 +40,7 @@ class UserFactory extends Factory
      */
     public function unverified(): static
     {
-        return $this->state(fn (array $attributes) => [
+        return $this->state(fn (array $attributes): array => [
             'email_verified_at' => null,
         ]);
     }

database/migrations/0001_01_01_000000_create_users_table.php

@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 use Illuminate\Database\Migrations\Migration;
 use Illuminate\Database\Schema\Blueprint;
 use Illuminate\Support\Facades\Schema;
@@ -11,7 +13,7 @@ return new class extends Migration
      */
     public function up(): void
     {
-        Schema::create('users', function (Blueprint $table) {
+        Schema::create('users', function (Blueprint $table): void {
             $table->id();
             $table->string('name');
             $table->string('email')->unique();
@@ -21,13 +23,13 @@ return new class extends Migration
             $table->timestamps();
         });
 
-        Schema::create('password_reset_tokens', function (Blueprint $table) {
+        Schema::create('password_reset_tokens', function (Blueprint $table): void {
             $table->string('email')->primary();
             $table->string('token');
             $table->timestamp('created_at')->nullable();
         });
 
-        Schema::create('sessions', function (Blueprint $table) {
+        Schema::create('sessions', function (Blueprint $table): void {
             $table->string('id')->primary();
             $table->foreignId('user_id')->nullable()->index();
             $table->string('ip_address', 45)->nullable();

database/migrations/0001_01_01_000001_create_cache_table.php

@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 use Illuminate\Database\Migrations\Migration;
 use Illuminate\Database\Schema\Blueprint;
 use Illuminate\Support\Facades\Schema;
@@ -11,13 +13,13 @@ return new class extends Migration
      */
     public function up(): void
     {
-        Schema::create('cache', function (Blueprint $table) {
+        Schema::create('cache', function (Blueprint $table): void {
             $table->string('key')->primary();
             $table->mediumText('value');
             $table->integer('expiration');
         });
 
-        Schema::create('cache_locks', function (Blueprint $table) {
+        Schema::create('cache_locks', function (Blueprint $table): void {
             $table->string('key')->primary();
             $table->string('owner');
             $table->integer('expiration');

database/migrations/0001_01_01_000002_create_jobs_table.php

@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 use Illuminate\Database\Migrations\Migration;
 use Illuminate\Database\Schema\Blueprint;
 use Illuminate\Support\Facades\Schema;
@@ -11,7 +13,7 @@ return new class extends Migration
      */
     public function up(): void
     {
-        Schema::create('jobs', function (Blueprint $table) {
+        Schema::create('jobs', function (Blueprint $table): void {
             $table->id();
             $table->string('queue')->index();
             $table->longText('payload');
@@ -21,7 +23,7 @@ return new class extends Migration
             $table->unsignedInteger('created_at');
         });
 
-        Schema::create('job_batches', function (Blueprint $table) {
+        Schema::create('job_batches', function (Blueprint $table): void {
             $table->string('id')->primary();
             $table->string('name');
             $table->integer('total_jobs');
@@ -34,7 +36,7 @@ return new class extends Migration
             $table->integer('finished_at')->nullable();
         });
 
-        Schema::create('failed_jobs', function (Blueprint $table) {
+        Schema::create('failed_jobs', function (Blueprint $table): void {
             $table->id();
             $table->string('uuid')->unique();
             $table->text('connection');

database/migrations/2025_12_25_051601_create_personal_access_tokens_table.php

@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 use Illuminate\Database\Migrations\Migration;
 use Illuminate\Database\Schema\Blueprint;
 use Illuminate\Support\Facades\Schema;
@@ -11,7 +13,7 @@ return new class extends Migration
      */
     public function up(): void
     {
-        Schema::create('personal_access_tokens', function (Blueprint $table) {
+        Schema::create('personal_access_tokens', function (Blueprint $table): void {
             $table->id();
             $table->morphs('tokenable');
             $table->text('name');

database/seeders/DatabaseSeeder.php

@@ -1,12 +1,14 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Database\Seeders;
 
 use App\Models\User;
 use Illuminate\Database\Console\Seeds\WithoutModelEvents;
 use Illuminate\Database\Seeder;
 
-class DatabaseSeeder extends Seeder
+final class DatabaseSeeder extends Seeder
 {
     use WithoutModelEvents;