Consolidate the copyright into a single meshterm.copyright_notice() beside
__version__ (was defined twice, disagreeing on wording, holder, and year
span). Every startup splash draws from it, so it can never drift.
Place it immediately under the wordmark, right-justified to the logo edge, so
the two read as one signed block. Simplify the display logic: it now rides
every splash that shows the logo (picker, spinner, PIN, notices) rather than
being dropped after the first selection.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>