Docs: clarify OpenAI Codex vs. "ChatGPT Work" branding

[hayesdavis]

OpenAI's naming around Codex and ChatGPT Work (https://chatgpt.com/work/) is genuinely confusing, and our docs should reference both correctly and explain the relationship instead of leaving readers to untangle it.

The confusion

As best we can tell: "ChatGPT Work" is an app/surface that rebrands and encompasses Codex, while Codex also continues to exist as its own coding/knowledge-work agent (~/.codex/sessions, the codex source Argus already parses). So "Work" both is Codex-branded and contains Codex, depending on where you look. This needs to be pinned down before we write about it, since users will see both names and won't know if they're the same thing, one contains the other, or they're separate products.

Task

• Confirm the actual current relationship between "Codex" and "ChatGPT Work" from OpenAI's own sources (https://chatgpt.com/work/, https://openai.com/codex/, and OpenAI's docs/announcements) — what's the product, what's the surface, what's the CLI, and which one produces the local ~/.codex/sessions transcripts Argus reads.
• Update the user-facing docs so the name(s) Argus uses match what users actually see in OpenAI's product, and briefly disambiguate the two where a reader might be confused. Pages that mention Codex today:
  • docs/supported-agents.md (source table + description, currently links https://openai.com/codex/)
  • docs/terminology.md
  • docs/index.md
  • docs/metric-views.md
• Decide and document the canonical product-name styling for whatever we land on, and add it to docs/contributing/voice-and-tone.md (Product-name styling) and docs/contributing/technical-writing.md (terminology list) alongside the existing Claude Cowork / Claude Chat guidance.
• Keep the internal source slug codex as-is (this is a docs/branding change only — no change to the codex producer, ~/.codex paths, or the source values in the store/schema).

Notes

• Related, now-closed: Add ChatGPT Work as a new session source #254 (ChatGPT Work as a potential new source) — that investigation is the likely place to confirm whether "Work" has any separate local artifact vs. just being the Codex sessions we already parse.
• Scope is documentation + the contributing style guides only. No code, no schema, no new source.