`to_rao` / `from_rao` live in `cli/swap_commands/helpers.py` but are used outside the CLI

[atoz96]

allways/cli/swap_commands/helpers.py:153-160 defines unit-conversion utilities, but unit conversion is not CLI-specific — view rendering, post_tx, and even rate-event display use them. Move them to allways/utils/misc.py (alongside the existing rao helpers) so non-CLI callers do not have to import from a CLI module.