A custom profile's menu gets Copy profile code, which puts one line of text
on the clipboard: icarus-theme: plus base64url of versioned JSON (name and
three colors). Import profile code, under New profile, opens a dialog that
prefills from the clipboard, previews the open map in the pasted colors,
and adds the profile. Junk, cut-off codes, codes from a newer Icarus, and
colors you already have each get one sentence instead of a silent failure.

Custom profiles now list oldest first, so an imported or new profile lands
at the end instead of wherever its random id sorts.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>