fix: lib/sh/util.sh: already_exists_msg(): changed calling convention to avoid it seeming like `return 0` is run if already_exists_msg() throws an error, when in fact already_exists_msg() is just a command that should be run before returning/errexiting

bugfix: lib/common.Makefile: $(wildcard/): need final pass with $(wildcard) to support inputs without wildcard chars

bugfix: lib/sh/local.sh: $sync_remote_url: jupiter user is always aaronmk, not the local user

*{.sh,run}: use standard WARNING syntax for warning labels

*{.sh,run}: use standard WARNING syntax for warning labels

fix: lib/sh/util.sh: verbosity_compat(): documented that this should not be run until right before executing an external command, so that it doesn't mess up the logging mechanism

bugfix: lib/sh/util.sh: functions called by pst(): commented out/removed logging calls that would have caused infinite recursion when pst()'ing a logging function

lib/sh/util.sh: echo_func(): get call context before wrapper(s), which is more useful for debugging. this uses skip_stack_frames()'s lookahead=1 mode.

fix: lib/sh/util.sh: skip_stack_frames() callers: updated for new skip_stack_frames rather than get_stack_frame behavior

lib/sh/util.sh: skip_stack_frames(): added lookahead support, which looks at entry after current to deterine whether to skip current. this is useful for skipping wrappers, by looking at the calling function's name.