feat: support resource limits on the build container

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`.

plugins/resource/src/triggers/triggers.go

@@ -18,6 +18,10 @@ func main() {
 
 	var err error
 	switch trigger {
+	case "docker-args-process-build":
+		appName := flag.Arg(0)
+		builderType := flag.Arg(1)
+		err = resource.TriggerDockerArgsProcessBuild(appName, builderType)
 	case "docker-args-process-deploy":
 		appName := flag.Arg(0)
 		processType := flag.Arg(3)