refactor(plugin): port security policy resolution to TypeScript

[kmbroai]

Summary

Replace the Python SECURITY.md resolver and its tests with a typed helper bundled alongside the MCP runtime. Policy discovery and root-to-leaf guidance use the existing Node launcher.

Changes

• Enforce scan-root containment and preserve symlink and junction behavior, byte limits, UTF-8 handling, home expansion, inventory ordering, accepted arguments, and output formats.
• Preserve POSIX path bytes and Windows UTF-16 process values and paths; establish Windows ancestry by comparing native volume and file identities while walking parent directories.
• Invoke launch_codex_security_mcp[.cmd] --helper resolve-security-md --repo PATH [--list | --scope PATH] [--out PATH], defaulting to stdout. Limit the SDK's Python interpreter instruction to .py helper scripts.
• Keep operator guidance focused on accepted options, quoted tilde paths, and output behavior. Replace complete Markdown snapshots with semantic source/content/order assertions and dedicated framing checks.
• Retain the compatible path resolver after native realpath comparisons showed different existing-file parent behavior. Remove the completed characterization probe and describe the active TypeScript policy helper in the native documentation.

Testing

• SDK/MCP type checks, formatting, CI-tool compilation, Rust formatting, both MSVC-target Clippy checks, Ruff, portable source checks, and all nine checker tests passed.
• Focused policy/launcher tests passed: 34 passed, with five Windows-only tests skipped locally. All 12 adapter normalization tests passed.
• Windows x64/arm64 CI exercises the actual helper and native binding, including directory-identity checks for scope and policy paths. The raw-path proof also runs on Node 20 and 22.
• Existing behavioral tests retain argument parsing, home expansion, file-parent resolution, missing-path, symlink-cycle, ordering, and raw-byte coverage.

Risk and rollout

Stacked on #798. The helper entrypoint changes from the Python script to the shared launcher, with callers updated together. Previously accepted arguments and home expansion remain supported intentionally. GNU Linux file/.. compatibility requires retaining the existing resolver; native realpath is not a drop-in replacement. Other Python helpers remain for subsequent migration slices. There are no new top-level CLI flags.

Public disclosure review

• No customer, partner, prospect, or user identities, data, or identifying details are included.
• No credentials, personal data, private source, scan findings, or nonpublic links or tickets are included.
• I reviewed the branch name, title, description, commits, changes, comments, logs, screenshots, attachments, and links for public disclosure.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
🔒 Security Review	✅ Completed 2026-09-07T11:36:06.721490Z	90e02bd	New commits

Security findings

Blocking findings (1)

• 🔴 Resolve helper Node outside the scanned repository · High · Dismissed · From earlier review · ad511ed

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" or "@codex security review".

Codex reacts with 👀 while any review is running, comments if it has suggestions, and reacts with 👍 once all reviews finish with no findings.

[chatgpt-codex-connector]

💡 Codex Security Review

Here are some automated security review suggestions for this pull request.

Reviewed commit: ad511edcbb

ℹ️ About Codex security reviews in GitHub

This is an experimental Codex feature. Security reviews are triggered when:

• You comment "@codex security review"
• A regular code review gets triggered (for example, "@codex review" or when a PR is opened), and you’re opted in so security review runs alongside code review

Once complete, Codex will leave suggestions, or a comment if no findings are found.

[mldangelo-oai]

Re-reviewed the exact current head and reconciled all prior threads. The compatibility behavior is well covered; the remaining comments are nonblocking simplification and documentation cleanup.