CRITICAL FIX: Move composer install after containers start

The previous setup scripts ran 'composer install' in a temporary container
before starting the actual containers. This caused vendor/ directory to be
created inside the temporary container and then deleted, leaving the host
filesystem without dependencies.

Changes:
- setup.bat: Move composer install to Step 4 (after containers start)
- setup.sh: Move composer install to Step 4 (after containers start)
- Use 'docker-compose exec' instead of 'docker-compose run --rm'
- This ensures vendor/ is written to the host filesystem via volume mount
- Added TEST_SETUP.md with comprehensive testing procedures

Now the vendor/ directory will persist correctly on Windows/WSL2 and the
app will load without 'vendor/autoload.php not found' errors.

This was the root cause of the setup not being truly '2-minute ready'.

setup.bat

@@ -34,11 +34,10 @@ if exist "src\.env.%DB%" (
     exit /b 1
 )
 
-REM Step 2: Install composer dependencies
-echo Installing composer dependencies...
+REM Step 2: Build containers
+echo Building Docker containers...
 docker-compose build
-docker-compose --profile %DB% run --rm app composer install --no-interaction
-echo Dependencies installed
+echo Containers built
 echo.
 
 REM Step 3: Start containers
@@ -47,7 +46,13 @@ docker-compose --profile %DB% up -d
 echo Containers started
 echo.
 
-REM Step 4: Wait for database
+REM Step 4: Install composer dependencies
+echo Installing composer dependencies...
+docker-compose exec app composer install --no-interaction
+echo Dependencies installed
+echo.
+
+REM Step 5: Wait for database
 if "%DB%"=="mysql" (
     echo Waiting for database...
     timeout /t 5 /nobreak >nul
@@ -61,27 +66,28 @@ if "%DB%"=="pgsql" (
     echo.
 )
 
-REM Step 5: Generate app key
+REM Step 6: Generate app key
 echo Generating application key...
 docker-compose exec app php artisan key:generate --force
 echo App key generated
 echo.
 
-REM Step 6: Run migrations
-echo → Running database migrations...
+REM Step 7: Run migrations
+echo Running database migrations...
 docker-compose exec app php artisan migrate --force
-echo ✓ Migrations completed
+echo Migrations completed
 echo.
 
-echo → Seeding database (roles, permissions, admin user)...
+REM Step 8: Seed database
+echo Seeding database (roles, permissions, admin user)...
 docker-compose exec app php artisan db:seed --force
-echo ✓ Database seeded
+echo Database seeded
 echo.
 
-REM Step 7: Create storage link
-echo → Creating storage symlink...
+REM Step 9: Create storage link
+echo Creating storage symlink...
 docker-compose exec app php artisan storage:link
-echo ✓ Storage linked
+echo Storage linked
 echo.
 
 REM Done