* fix(web): restore diff expansion for committed-source review rows
#1097 narrowed the expansion gate to `source === "uncommitted"` to dodge a
trailing-context crash, which silently dropped expand controls for committed
files — the bulk of a review. The crash is now caught by the reparse guard in
useExpandableDiff, so re-enable expansion for committed rows, fetching the old
side from the repo's base branch (not HEAD, which already has the commits).
Extracts the decision into a pure `resolveDiffExpansion` helper and adds a
multi-repo guard so a committed file never borrows another repo's base branch.
* fix(web): guard diff-expansion base fallback to single-repo tasks
Resolve baseBranchByRepo once in ReviewDiffList (not per row) and only expose a
fallback base branch when the task has exactly one repo, so a committed file
with no repository_name in a multi-repo task no longer borrows an arbitrary
repo's base branch. Addresses Greptile/cubic review feedback.
José Almeida
77f7924004