Bug fixes:
- Fix OSC8 format strings (backslash escape layering) in modern-backend.org
- Test format string had single backslash instead of double, causing
unclosed CL string that cascaded through 3 subsequent test forms
- Implementation format string had leading escaped quote (not a string
opener) and triple-backslash ending (also not a string terminator)
- Fix missing closing parens in border-char-rounded and border-char-double tests
- Fix ASDF input-tests pathname (file lives in tests/, not src/components/)
New features:
- Implement suspend-backend / resume-backend protocol methods
- modern-backend: exit/enter alt screen, re-enable mouse/kitty/bracketed-paste
- simple-backend: no-ops (no terminal state to preserve)
Infrastructure:
- Update test suite to cover suspend/resume (backend + modern-backend suites)
- 454 checks, 100% pass across 14 test suites
The osc8-link implementation and its test both had doubled
backslashes (\\ -> \\) in their format strings, producing two
literal backslashes at runtime instead of the single backslash
needed for the OSC 8 string terminator (ST = ESC \).
Fix: change \\ to \\ in both the implementation and test format
strings. The tangled .lisp files now have correct escaped
backslashes (\) producing one backslash in the runtime string.
Additionally clean up a patch artifact that left a stray backslash
before the opening quote.
