Both helpers wrap `run /bin/bash -c "..."` with the env vars dokku plugin scripts and `plugn` need, replacing the long inline boilerplate that was duplicated across `tests/unit/resource_3.bats` and the new `core-post-extract` regression tests in the builder bats files.
Adds a `docker-args-process-build` trigger to the resource plugin so
limits set via `dokku resource:limit --process-type build APP` are
applied during the build phase. Only `build.limit.*` properties are
read - defaults do not inherit, since builds typically need more memory
than runtime and a leaked tiny default would cause confusing OOM
failures. Reservations are never applied at build time. Allowed flags
are filtered per builder: herokuish gets cpu, memory, memory-swap, and
nvidia-gpu; dockerfile gets memory and memory-swap; pack, nixpacks,
railpack, lambda, and null emit nothing because their underlying CLIs
do not accept docker run resource flags. The dockerfile builder
whitelists the new memory flags and corrects pre-existing typos where
`--ssh` mapped to `--platform` and `--ulimit` mapped to `--tag`.
