Replace hatch-pet curated skill workflow

[richardopenai]

Summary

• add the curated hatch-pet-v2 skill for Codex-compatible pet spritesheet generation
• keep image generation lightweight with per-job workers, storage controls, and visual QA guidance
• add adaptive brand discovery briefs while keeping generation prompts compact

Verification

• python -m py_compile skills/.curated/hatch-pet-v2/scripts/*.py
• ruff check skills/.curated/hatch-pet-v2/scripts
• smoke-tested prepare_pet_run.py with and without a brand discovery brief

[chatgpt-codex-connector]

Codex Review: Something went wrong. Try again later by commenting “@codex review”.

Provided git ref refs/pull/399/head does not exist

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".