Add a local conflict resolution workflow that allows resolving PR
merge conflicts from the review center. The change implements host and
repository matching, prepares and merges branches locally, opens the
resolve editor, and tracks a multi-phase state machine to continue,
abort, or push the resolved branch back to the remote.
- Core resolution logic to locate matching repos, prepare merges,
and manage phases (preparing → conflicts → ready-to-push → complete).
- UI wiring and callbacks to start, reopen, continue, abort, and push
local resolutions from the review center.
- Helpers to open the conflict editor, monitor merge state, and mark
completion after a successful push.
Christoph
c46a875a91