Reopening a GitHub issue/PR drawer paid full IPC + `gh` startup latency on
every open. Two changes here:
1. Module-level SWR cache in GitHubItemDialog.tsx keyed by
(repoPath, issueSourcePreference, type, number). Reopening within 30s
paints cached data instantly; older entries paint stale-then-refresh.
Concurrent opens dedupe on a shared in-flight promise. Mutation
handlers invalidate by (repo, type, number); a cache-generation
counter prevents in-flight refetches from resurrecting stale data
after a mid-flight invalidation.
2. Collapsed GraphQL query for issue details replaces 3 serial `gh`
subprocesses (REST issue + REST comments + GraphQL participants) with
one round-trip. Falls back to the legacy fan-out on any GraphQL error
so historical contract is preserved.
Cross-window invalidation rides a new `gh:workItemMutated` IPC broadcast
that skips the originating sender (the source already updated its cache
optimistically — re-broadcasting would race the optimistic write).
`addIssueComment` now takes a `type` so the broadcast scopes correctly
when a PR shares its number with an issue.
Co-authored-by: Orca <help@stably.ai>
