feat: add auto optimization draft pr workflow

[Pigbibi]

Summary

• add a repo-local workflow that turns monthly-optimization-task issues into draft PRs for low-risk auto-pr-safe tasks
• add parser utilities and tests for selecting eligible issue actions and preparing PR metadata
• add workflow_dispatch support to CI so automation branches can still be validated

Testing

• python3 -m unittest tests/test_prepare_auto_optimization_pr.py tests/test_auto_optimization_pr_workflow_config.py
• python3 -m py_compile scripts/prepare_auto_optimization_pr.py
• uvx ruff check scripts tests src
• ruby -e 'require "yaml"; Dir[".github/workflows/*.yml"].each { |f| YAML.load_file(f) }; puts "yaml ok"'

Notes

• The full local test_catalog suite still needs quant_platform_kit installed; CI will cover that dependency in the GitHub runner.