v1.0.0 release

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

src/backend/classes.lisp

@@ -8,6 +8,16 @@
 (defgeneric shutdown-backend (backend)
   (:method ((b backend)) (values)))
 
+(defgeneric suspend-backend (backend)
+  (:documentation "Temporarily suspend the backend, restoring terminal to normal state.
+Called before SIGTSTP or similar suspension. Application should redraw after resume.")
+  (:method ((b backend)) (values)))
+
+(defgeneric resume-backend (backend)
+  (:documentation "Re-initialize the backend after suspension.
+Called after SIGCONT or similar resume. Re-enables raw mode and backend features.")
+  (:method ((b backend)) (values)))
+
 (defgeneric backend-size (backend)
   (:method ((b backend))
     (values 80 24)))