Fix text drift in workflow docs and log error extractor help

[github-actions]

Summary

This PR resolves the text-auditor findings in issue #1222 by aligning user-facing docs/help text with current behavior.

Changes

1. Updated continuous-improvement workflow lists to include missing workflows:
   • README.md
   • docs/workflows/gh-agent-workflows.md
   • Added: product-manager-impersonator, refactor-opportunist
2. Updated scripts/extract-log-errors.py module help text:
   • grep patterns → regex patterns
   • Default pattern list in the docstring now matches implemented defaults (DEFAULT_PATTERNS) for the listed items.
3. Reworded claude-workflows/README.md to avoid claiming every action directory includes local example.yml/README files.

Validation

• Ran test suite: pytest -q (53 passed)

Closes #1222.

Note

🔒 Integrity filter blocked 1 item

The following item were blocked because they don't meet the GitHub integrity level.

• #1175 list_pull_requests: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".

To allow these resources, lower min-integrity in your GitHub frontmatter:

tools:
  github:
    min-integrity: approved  # merged | approved | unapproved | none

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What is this? | From workflow: Trigger Text Auditor

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