test(tui): cover CJK playbook editing geometry

[edwin-zvs]

Summary

• audit playbook editor cursor/render geometry around wide CJK glyphs
• make the paint differential assert CJK glyph cells directly across narrow and wide layouts
• cover wrapped cursor round-trips, hit-testing, insertion, movement, deletion, selection, and cut

No production drift was demonstrated; this is a focused regression-test change under the existing spec 0093 contract.

Tests

• cargo test -p construct-cli playbook_cjk -- --nocapture
• cargo test -p construct-cli playbook_cursor_math_matches_painted_buffer_differential -- --nocapture
• env -u NO_COLOR cargo test -p construct-cli (1418 unit tests + reconnect integration test)
• cargo build