fix: Remove hardcoded credentials from test_benchmark_api.py

- Replace hardcoded API_KEY with os.getenv('TEST_API_KEY')
- Replace hardcoded HF_TOKEN with os.getenv('TEST_HF_TOKEN')
- Replace hardcoded API_BASE with os.getenv('TEST_API_BASE')
- Replace hardcoded MODEL with os.getenv('TEST_MODEL')
- Add test credentials patterns to .gitignore
- Fixes GitHub Security Alert #8 (py/clear-text-storage-sensitive-data)

Sensitive data is now loaded from environment variables instead of clear text.

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

.gitignore

@@ -81,3 +81,8 @@ QWEN.md
 
 # Internal documentation (not for public)
 TODO.md
+
+# Test credentials
+.env.test
+*.test.env
+test_credentials.py