Add AI-HPP v4.2 auto-archive workflow

[tryblackjack]

Motivation

• Add the AI-HPP v4.2 auto-archive workflow to enforce the canonical root layout and automatically move unexpected root items into archive/<date>/auto/ without deleting anything.
• Ensure the new workflow is deterministic, minimal, and runs on ubuntu-latest using actions/checkout@v4 to match the v4.2 rules.

Description

• Replaced the existing .github/workflows/auto-archive.yml contents with the provided AI-HPP v4.2 workflow that installs actions/setup-python@v5 and runs a shell auto-archive script.
• The workflow enforces the allowed root items list, builds a grep-safe PATTERN, moves unexpected items into archive/$(date +%Y-%m-%d)/auto/, and writes a .reason file next to each moved item.
• Adjusted the job name to archive and added a Commit & Push step that configures author identity and pushes changes if any root items were archived.

Testing

• Listed existing workflows with ls -1 .github/workflows to confirm detected files before modification and ensure no unexpected files were targeted. (succeeded)
• Validated the new YAML file syntax using Ruby's YAML.load_file which parsed .github/workflows/auto-archive.yml successfully. (succeeded)
• Attempted Python pyyaml validation but pip installation failed due to environment package/proxy restrictions, so Ruby validation was used instead. (pip/pyyaml install failed, YAML parse via Ruby succeeded)
• Ran git status --short to verify that the only pending change was the updated auto-archive.yml workflow file. (succeeded)

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[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Escape allowed names before regex matching

Building PATTERN by joining raw filenames makes grep -E treat metacharacters in allowed names as regex operators, so entries like README.md and .gitignore match unintended names (for example READMEXmd), which lets non-canonical root items bypass archiving. Quote or escape each allowed literal before composing the alternation so matching stays exact.

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