Summary

• Add opt-in GitHub pull request notifications for pinned repositories.
• Notify on new PRs, PR updates/state changes, review requests, and new comments, each controlled by Settings > Notifications.
• Route notification clicks either to the default browser or directly into RepoBar's Issue Navigator with the PR preselected.
• Reuse the shared RepoBar notification pipeline for local sync notifications and PR notifications.

Closes #57

How notifications work

• RepoBar only monitors pinned repositories.
• When PR notifications are first enabled, RepoBar clears the PR notification snapshot store and refreshes immediately.
• The first refresh records the current PR state without sending a backlog of notifications.
• For each monitored repo, RepoBar stores PR snapshots plus a repo-level baseline timestamp.
• A PR is considered new only when its created_at is newer than the repo baseline, so old PRs that re-enter the recent window do not fire as new.
• PR updates compare stored updated_at, state, and merge state.
• Review-request notifications compare requested users and requested teams.
• Comment notifications compare issue conversation comments plus PR review comments.
• Comment-count fetching is opt-in: normal menu PR loads stay lightweight, and the extra comment-count REST calls only run when comment notifications are enabled.
• Turning comment notifications on primes counts first, so existing comments do not replay as new notifications.

Settings UI

• Pull request notifications now live in a dedicated Settings > Notifications tab.
• Advanced keeps the GitHub References and archive/debug-style settings separate from notification preferences.

Click behavior

• Default browser opens the PR URL normally.
• Issue Navigator stores PR metadata in the notification payload and opens Issue Navigator with that PR as the initial match.
• Older notifications without metadata still open Issue Navigator empty instead of crashing or misrouting.

Review cleanup

• Rebased on current main.
• Split the branch into small reviewable commits.
• Added a changelog entry thanking @Whiteknight07.
• Hardened detector state decoding for older saved snapshots.
• Added regression coverage for first-refresh baselining, old PR re-entry, comment tracking, review requests, state changes, and notification click routing.

Validation

• pnpm check - passed, 403 tests in 86 suites.
• codex-review --parallel-tests "pnpm check" - clean, no accepted/actionable findings.
• pnpm restart - relaunched local debug app from /Users/steipete/Projects/RepoBar/.build/arm64-apple-macosx/debug/RepoBar.app/Contents/MacOS/RepoBar.