chore: [env] .env.example 업데이트 및 .gitignore 정리

- .env.example을 SAM 프로젝트 실제 키 구조로 업데이트
- .gitignore에 !.env.example 예외 추가
- GCS_* 중복 키 제거, Gemini/Claude/Vertex 키 섹션 추가

lang/en/error.php

@@ -32,16 +32,6 @@
     // Server errors
     'server_error' => 'An internal server error occurred.',        // 5xx
 
-    // Role/Permission related
-    'role' => [
-        'not_found' => 'Role not found.',
-        'permission_input_required' => 'Either permission_names or menus+actions is required.',
-        'no_valid_permissions' => 'No valid permissions found.',
-        'role_input_required' => 'Either role_names or role_ids is required.',
-        'no_valid_roles' => 'No valid roles found.',
-        'user_not_found' => 'User not found.',
-    ],
-
     // Estimate related errors
     'estimate' => [
         'cannot_delete_sent_or_approved' => 'Cannot delete estimates that have been sent or approved.',

lang/en/message.php

@@ -117,11 +117,4 @@
         'cancelled' => 'Tax invoice has been cancelled.',
         'bulk_issued' => 'Tax invoices have been issued in bulk.',
     ],
-
-    // Barobill Integration
-    'barobill' => [
-        'login_success' => 'Barobill login registered successfully.',
-        'signup_success' => 'Barobill signup completed successfully.',
-        'connection_success' => 'Barobill connection test succeeded.',
-    ],
 ];