Oddly my env was borked bc this (apparently missed by `uv`?) sub-dep
wasn't installed and then `stackscope` was silently failing import and
caused the shield-pause test to also fail (since it couldn't match the
expected `log.devx()` on console). The import failure is not very
explanatory due to the `log.warning()`; change it to `.error()` level.
Also, explicitly import `_sync_pause_from_builtin` in
`examples/debugging/restore_builtin_breakpoint.py` to ensure the ref is
exported properly from `.devx.debug` (which it wasn't during dev of the
prior commit Bp).
4fca7317ea