feat(cli): draft SECURITY.md for owner review (#536)

* refactor(sdk): share Codex session setup

* feat(cli): draft SECURITY.md for owner review

* fix(sdk): keep policy previews scoped and terminal-safe

* fix(cli): keep policy inputs and previews scoped

* fix(sdk): package policy helpers and handle missing links

* fix(sdk): validate policy paths before model access

* refactor(cli): reuse scan setup across commands

* fix(sdk): validate policy inputs before drafting

* refactor(policy): keep reporting checks at application

* fix(cli): honor policy settings and cancellation

* fix(sdk): preserve policy evidence and owner answers

* fix(sdk): isolate policy instructions from artifact checkouts

* fix(policy): harden draft generation boundaries

* fix(policy): clarify draft generation and review guidance

* fix(policy): narrow runtime reads and preserve source evidence

* fix(policy): enforce component and runtime read boundaries

* fix(policy): preserve macOS framework Python environments

* fix(policy): simplify guidance and validate draft completion

* refactor(policy): simplify draft generation

* fix(policy): keep CLI types out of public SDK declarations

* fix(policy): constrain linked guidance and tool environments

* fix(policy): exclude Git metadata from model reads

* fix(policy): preserve literal metadata exclusions

* fix(policy): confirm metadata directories with Git

* fix(policy): resolve metadata without repository config

* fix(policy): share Git metadata exclusions across policy reads

* fix(policy): protect alternate Git object stores

* fix(policy): share object-store discovery across metadata

* fix(policy): serialize permission paths as TOML values

* test(policy): load SDK defaults in native CLI regression

---------

Co-authored-by: mldangelo-oai <269034524+mldangelo-oai@users.noreply.github.com>
Co-authored-by: kmbroai <272643392+kmbroai@users.noreply.github.com>
Co-authored-by: Kyle Brown <kyleb@openai.com>
Co-authored-by: mldangelo-oai <mldangelo-oai@users.noreply.github.com>