fix(examples): preserve Bitbucket OCR diagnostics

[a1212a11]

Summary

• capture OCR stderr and its exit status in the Bitbucket Pipelines example
• print diagnostics and preserve non-zero OCR failures while keeping normal findings successful
• update the Bitbucket troubleshooting guidance

Validation

• parsed the pipeline YAML successfully
• exercised the extracted shell block for findings (exit 0), infrastructure failure (exit 23), and empty output (exit 1)
• ran git diff --check

Closes #484

[CLAassistant]

All committers have signed the CLA.

[github-actions]

✅ OpenCodeReview: No comments generated. Looks good to me.

[lizhengfeng101]

LGTM