* feat: add testsuite

* ci: trigger test workflow on any branch

* chore: remove optional documentation files to keep PR focused

* docs: translate testsuite README to English

* docs: remove testsuite README to keep PR minimal

* fix: ensure reliable PostgreSQL authentication in container mode

- Explicitly set username=postgres and password=my-secret
- Add wait strategy for container readiness
- Ensures consistent authentication across all environments

* chore: remove Chinese comment, use English for open source

* docs: add comment explaining authentication configuration

* ci: restrict workflow to main branch only

* refactor: rename env var to USE_TEST_CONTAINERS for better clarity

- Changed from WPGX_TEST_USE_CONTAINER to USE_TEST_CONTAINERS
- Updated all files: testsuite.go, Makefile, README.md, examples, workflow
- More concise and follows common naming conventions

* docs: translate Chinese comments to English and add fix/** branch

- Translate all Chinese comments in examples to English
- Add fix/** branch to PR workflow triggers
- Ensures code is fully English for international contributors

* refactor: remove import alias and extract constants

- Remove sqlsuite alias, use testsuite package name directly
- Extract container configuration values to constants (image, user, password, timeout)