feat(more): exit_on_eof option

[aaron-ang]

Fix part of #2320.

[codspeed-hq]

Merging this PR will not alter performance

✅ 317 untouched benchmarks
⏩ 46 skipped benchmarks¹

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_{Comparing aaron-ang:more-options (a86c267) with main (94b06d9)}

Footnotes

1. 46 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[sylvestre]

please split this PR into several

[aaron-ang]

@sylvestre this PR now covers exit_on_eof option only, with some minor refactoring on existing structs and tests. Once this is merged, I will add the remaining option implementations (logical and no_pause)

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/tail/follow-name (fails in this run but passes in the 'main' branch)
Skipping an intermittent issue tests/shuf/shuf-reservoir (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/sort/sort-stale-thread-mem (passes in this run but fails in the 'main' branch)

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/tail/follow-name (fails in this run but passes in the 'main' branch)
Skipping an intermittent issue tests/shuf/shuf-reservoir (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/sort/sort-stale-thread-mem (passes in this run but fails in the 'main' branch)

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/shuf/shuf-reservoir (fails in this run but passes in the 'main' branch)
Skip an intermittent issue tests/sort/sort-stale-thread-mem (fails in this run but passes in the 'main' branch)

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/tail/inotify-dir-recreate (passes in this run but fails in the 'main' branch)

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/tail/inotify-dir-recreate (passes in this run but fails in the 'main' branch)

[aaron-ang]

@sylvestre slimmed this PR down per your request. It now contains only the exit_on_eof feature (~50 lines):

• Options::exit_on_eof (replaces _exit_on_eof), with POSIXLY_CORRECT + tty gate per the spec
• Pager honors the flag in process_events and exits early from more() after the initial draw when EOF is already reached
• Integration test test_space_at_eof_does_not_exit_without_exit_on_eof; existing pty tests set POSIXLY_CORRECT=1 to keep behavior under test
• -e/--exit-on-eof added to test_valid_arg

The previously bundled refactors (Input struct, highlight_text/tty-gate helpers, test infra, renames, pattern lifetime) are deferred to follow-up PRs. Rebased on main.

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/cut/bounded-memory (fails in this run but passes in the 'main' branch)
Skip an intermittent issue tests/tail/retry (fails in this run but passes in the 'main' branch)
Skip an intermittent issue tests/tail/tail-n0f (fails in this run but passes in the 'main' branch)
Skipping an intermittent issue tests/date/date-locale-hour (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/tail/follow-name (passes in this run but fails in the 'main' branch)
Skip an intermittent issue tests/pr/bounded-memory (was skipped on 'main', now failing)