Propagate errors from FunctionRunner::RegisterWorkersb/compute-batch

Change RegisterWorker return type from void to [[nodiscard]] bool across
the FunctionRunner hierarchy so callers can detect registration failures
at the point of registration rather than at action execution time.

- FunctionRunner pure virtual: void -> [[nodiscard]] bool
- LocalProcessRunner: always returns true (debug dump only)
- RemoteHttpRunner: returns false on the three HTTP error paths (removes
  the TODO comments), true on success/already-known
- BaseRunnerGroup: returns true only if all runners succeeded
- Callers in computeservice.cpp log warnings on failure but continue
  best-effort

0 files changed, 0 insertions, 0 deletions