Branches plugin duplicates every dry-run entry once per configured branch #1026

In nop mode, the branches plugin reports each planned change N times, where N is the number of configured branches with a protection key.

sync() in lib/plugins/branches.js declares a single resArray outside the per-branch .map(), pushes each branch's NopCommands into it, and each callback returns that same array. Promise.all then yields N references to one array, and the final res.flat(2) inlines its full contents N times. A config with branches: [master, develop], both with protection changes, produces 8 NopCommands instead of 4 (each one twice).

Downstream, handleResults mostly masks this in check-run output because its duplicate filter compares only type/repo/plugin — but that same filter also throws away legitimately different rows with matching keys, so the dry-run report for a repo with two protected branches shows only the first branch's diff. One bug hiding another.