Since bf1e6fca kbApplyCapsUtf8 wanted 4 bytes free before each codepoint;
the ABC grid passes a 3-byte cell buffer, so every cell came out empty (T9
and CardKB Compact draw no such cells, so it went unnoticed). A codepoint
is now copied when it fits with the NUL.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>