PR status indicators per worktree (open / draft / merged / closed)

[davidtaing]

Summary

Show each worktree branch's GitHub PR lifecycle state so you can tell at a glance which worktrees are done (merged), abandoned (closed), or still in flight (open/draft) — the key input to "can I delete this worktree?"

This is the networked half of worktree status; the offline local-sync half (ahead/behind/dirty) is tracked in #13.

Relationship to #13 — progressive enhancement

These two are designed as one layered feature, not two disconnected columns:

• Local sync indicators: ahead / behind / dirty per worktree #13 (local sync) is the always-on baseline. Computed from git alone, offline, no auth — fine to run in the default snapshot.
• This issue (PR status) is the enhancement layer. When the user has connected GitHub (gh auth present and the feature enabled), PR state is layered onto / alongside the same status column. When GitHub is not connected, the view falls back cleanly to just the Local sync indicators: ahead / behind / dirty per worktree #13 baseline — no errors, no gaps.

So the mental model is: worktree status always shows local sync; connect GitHub to additionally see PR state. Build #13 first; this layers on top.

States (first cut — states only)

Per branch with a PR:

• none — no PR for this branch
• draft — PR open, draft (not yet asking for review)
• open — PR open, ready for review
• merged — PR merged (worktree is likely safe to delete)
• closed — PR closed without merge (abandoned — distinct from merged)

Why

"Merged" and "closed" are the strongest signals that a worktree is disposable; "draft" vs "open" distinguishes work-in-progress from review-ready. Pairs with #13: merged + synced = safe to remove.

Enablement

• Gate on connecting GitHub: detect existing gh auth and turn the layer on via a flag/config (e.g. --pr / a config key). No bespoke auth flow — lean on gh.
• Must degrade gracefully when unavailable, unauthenticated, offline, or the remote isn't GitHub: silently fall back to the Local sync indicators: ahead / behind / dirty per worktree #13 baseline, never error the whole view.

Implementation notes

• Data source: gh / GitHub API. One batched call covers all branches: gh pr list --json number,headRefName,state,isDraft,... (plus a query for merged/closed). Avoid per-branch calls.
• Likely restricted to -w live mode and/or behind the enable flag, given the cost. Cache results between refreshes; don't refetch every 2s tick — respect rate limits.
• Render: a compact glyph/short label per worktree row (e.g. merged, draft, ↑PR#123), layered onto the Local sync indicators: ahead / behind / dirty per worktree #13 status column. Coordinate column layout with Local sync indicators: ahead / behind / dirty per worktree #13.
• GitHub-only for now; design the lookup so a future GitLab/other forge backend could slot in.

Acceptance criteria

• With GitHub connected, worktree rows show PR state: none / draft / open / merged / closed.
• merged and closed are visually distinct.
• Without GitHub connected (no gh, no auth, offline, non-GitHub remote), the view falls back to the Local sync indicators: ahead / behind / dirty per worktree #13 baseline with no errors.
• PR data is cached, not refetched every refresh tick.
• Feature is opt-in / gated on connecting GitHub; the default offline snapshot is unaffected.

Out of scope / follow-ups

• CI check status (pending/passing/failing) on open PRs — future enhancement.
• Review status (approved/changes-requested) — future enhancement.
• Non-GitHub forges.