Fix Truncater counting OSC hyperlink payloads as printable width

[trippyogi]

Summary

Fixes #614

CLI::UI::Truncater only skipped CSI sequences (ESC [), so OSC hyperlink payloads (ESC ]…) were counted toward printable width and spinner titles truncated early even when ANSI.printing_width was correct.

This change teaches Truncater to consume OSC sequences (BEL and ST / ESC \), close an open OSC 8 hyperlink before emitting the truncation marker when a cut removes the original close, and keep OSC 8 open-state across unrelated OSC sequences (e.g. OSC 9) so a later truncate still closes the link.

Overlap with #624

#624 also covers this class of terminal-width/OSC issues as part of a much broader layout/parser change set, currently aimed at the pending 3.0 work rather than a minimal mainline fix. This PR is intentionally scoped to #614 on current main so maintainers can take the narrow fix independently if desired.

Test plan

• Exact Truncater counts OSC sequence contents (hyperlinks) as printable width #614 reproduction: formatted hyperlink fits within width and is unchanged
• Truncation inside an OSC 8 hyperlink emits OSC 8 close before TRUNCATED
• BEL-terminated OSC sequences are ignored for width
• OSC 8 remains open across an unrelated OSC (e.g. OSC 9), then closes on truncate
• bundle exec rake (full suite + RuboCop) — blocked locally on Windows (sorbet-static has no x64-mingw-ucrt platform); please rely on CI

bundle exec rake
# or focused:
bundle exec ruby -Ilib:test test/cli/ui/truncater_test.rb