Desktop: enrich GitHub PR link hover preview with PR state color

Feature request

Codex Desktop currently shows a plain URL tooltip when hovering over a GitHub pull request link in a chat transcript. Claude Code's macOS app has a more useful behavior: hovering a PR link opens a compact rich preview card with the PR state visibly color-coded.

I would like Codex Desktop to emulate that behavior for GitHub PR links.

Why it matters

In agent-heavy workflows, PR links show up constantly in final status messages and handoff summaries. A hover preview that shows the PR state removes a small but repeated verification step: I can immediately tell whether a PR is open, merged, closed, or draft without opening GitHub.

This is especially useful when scanning many Codex threads or validating that a prior agent actually shipped and merged the work it claimed.

Suggested behavior

When hovering a GitHub PR URL such as:

github.com/<owner>/<repo>/pull/<number>

show a rich preview card instead of only the raw URL tooltip.

Recommended fields:

• State chip: Open / Merged / Closed / Draft / Unavailable
• Color treatment:
• Open: green
• Merged: purple
• Closed, unmerged: red
• Draft or unavailable: muted/gray
• Repository and PR number, e.g. openai/codex #1234
• PR title
• Author or org
• Updated/created age
• Changed lines and file count, if available
• Optional: CI/check state if cheaply available

Interaction notes

• Use existing GitHub auth if available; otherwise fall back gracefully to public metadata or the plain URL tooltip.
• Avoid blocking hover rendering on slow network calls; show a lightweight loading/fallback state.
• Cache PR metadata briefly per URL so repeated hovers do not spam GitHub.
• Keep the URL accessible/copyable from the preview.
• Preserve current behavior for non-GitHub links.

Visual parity target

Claude Code's macOS app displays a compact hover card with a colored state chip, PR title, repository/PR number, line delta, and file count. Codex Desktop's current hover only shows the URL. The request is to bring Codex's PR hover affordance up to that same quick-verification level.