Add Codex integration and installer support

[artile]

Summary

• add a Codex integration that packages The Agency as one public meta-skill with internal role sub-skills and NEXUS references
• extend convert/install scripts and README docs to support codex
• add the generated integrations/codex/ skill package and refresh multi-tool docs

Verification

• bash -n scripts/convert.sh scripts/install.sh
• ./scripts/convert.sh --tool codex
• ./scripts/install.sh --tool codex

[msitarzewski]

Great to see Codex support! We definitely want this integration.

To keep things consistent with how we handle other tools, we'd like to see this wired into the conversion/install pipeline rather than pre-generated files checked into the repo. This keeps the repo lightweight and ensures Codex files stay in sync when agents are added or updated.

Here's the pattern (same as Cursor, Aider, Windsurf, etc.):

1. Add a convert_codex() function to scripts/convert.sh — reads agent .md files and outputs Codex-format files to integrations/codex/
2. Add an install_codex() function to scripts/install.sh — copies generated files to the right location
3. Remove the pre-generated files — they'll be regenerated on demand via ./scripts/convert.sh --tool codex

Take a look at convert_cursor() or convert_opencode() in scripts/convert.sh for examples of the pattern. Each converter reads the YAML frontmatter + body and outputs the tool-specific format.

End result for users:

./scripts/convert.sh --tool codex
./scripts/install.sh --tool codex

Happy to help if you have questions about the structure!

[msitarzewski]

Hey @artile — the Codex integration approach is solid, and the convert.sh + install.sh additions are well-structured.

However, the 92 pre-generated skill files in integrations/codex/ shouldn't be committed to the repo. We follow a pattern where convert.sh generates integration files locally and the output directories are gitignored (see .gitignore — antigravity, gemini-cli, opencode, cursor, aider, windsurf, and openclaw outputs are all excluded).

Could you update the PR to:

1. Add integrations/codex/agency-agents/ to .gitignore (keep only the README)
2. Remove the 92 pre-generated files from the PR
3. Keep the convert.sh and install.sh changes (those are the valuable part)

Users run ./scripts/convert.sh --tool codex to generate the files locally, same as every other integration. This keeps the repo clean and ensures the output is always in sync with the source agents.