Subsequent escapes included in Truncate

[clipperhouse]

When a string is truncated and includes escape sequences, the string may be left “open ended”, i.e. the later reset code will not be there, and in a terminal this would therefore affect all following text. Like any other markup, really.

This PR changes Truncate* to scan the string filling the truncation point, collecting the subsequent escape code, and appending them. They won’t be visible, but they will offer “closure” of earlier sequences.

This PR does not evaluate the escape, only identifies and includes.

Also rename IgnoreControlSequences → ControlSequences. We’re not ignoring them, per se, rather it’s a new mode that does different things.

[Copilot]

Pull request overview

This PR improves terminal-safety of truncated strings by preserving ANSI/ECMA-48 escape sequences that occur after the truncation point (to avoid “open-ended” styling like color bleed), and renames the option controlling escape-sequence handling from IgnoreControlSequences to ControlSequences.

Changes:

• Update TruncateString/TruncateBytes to append subsequent ANSI escape sequences after truncation when Options.ControlSequences is enabled.
• Rename Options.IgnoreControlSequences → Options.ControlSequences across code, tests, docs, and fuzzing.
• Add benchmarks for truncation performance with/without escape-sequence preservation.

Reviewed changes

Copilot reviewed 7 out of 8 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
width.go	Renames option; updates truncation logic to preserve trailing escape sequences; updates method docs.
width_test.go	Updates tests to new option name and adds truncation expectations including preserved trailing sequences.
graphemes.go	Wires Options.ControlSequences into the uax29 grapheme iterator.
fuzz_test.go	Updates fuzz option matrices and invariants for renamed field.
truncate_bench_test.go	Adds microbenchmarks for truncate behavior with ANSI-heavy inputs.
README.md	Updates public documentation for the renamed option.
CHANGELOG.md	Updates release notes for the renamed option and new truncation behavior.
.gitignore	Ignores *.test artifacts.

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