feat(cli): color-coded diff output + -h short flag for --help (#185)

diff.py — color-coded status lines A (added) → green D (deleted) → red M (modified) → yellow R (moved) → cyan Child symbol ops inherit the same colour scheme: green for added symbols, red for removed, yellow for changed.

app.py — context_settings with help_option_names All five Typer instances (cli, plumbing_cli, midi_cli, code_cli, coord_cli, bitcoin_cli) now set context_settings with help_option_names=['-h', '--help'] so -h works at every level of the command tree.

Co-authored-by: Gabriel Cardona <gabriel@tellurstori.com>