The workflow was failing because it was running inside 'weed' directory,
but the tests are at the repository root. Removed working-directory
default and updated relative paths to weed source.
- Create new workflow for S3 Tables integration testing
- Add build verification job for s3tables package and s3api integration
- Add format checking for S3 Tables code
- Add go vet checks for code quality
- Workflow runs on all pull requests
- Includes test output logging and artifact upload on failure
