Remove MSW handlers and update demo credentials for improved standardization

- Deleted `admin.ts`, `auth.ts`, and `users.ts` MSW handler files to streamline demo mode setup.
- Updated demo credentials logic in `DemoCredentialsModal` and `DemoModeBanner` for stronger password requirements (≥12 characters).
- Refined documentation in `CLAUDE.md` to align with new credential standards and auto-generated MSW workflows.

backend/tests/core/test_config.py

@@ -172,7 +172,7 @@ class TestProjectConfiguration:
     def test_project_name_default(self):
         """Test that project name is set correctly"""
         settings = Settings(SECRET_KEY="a" * 32)
-        assert settings.PROJECT_NAME == "App"
+        assert settings.PROJECT_NAME == "PragmaStack"
 
     def test_api_version_string(self):
         """Test that API version string is correct"""