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/modern-tests.lisp

@@ -72,7 +72,7 @@
 (test osc8-escape
   "OSC 8 hyperlink escape wraps text"
   (is (equal (cl-tty.backend::osc8-link "http://example.com" "click here")
-             (format nil "~C]8;;http://example.com~C\click here~C]8;;~C\"
+             (format nil "~C]8;;http://example.com~C\\click here~C]8;;~C\\"
                      #\Esc #\Esc #\Esc #\Esc))))
 
 (test hex-color-parsing
@@ -101,10 +101,16 @@
   (is (equal (cl-tty.backend::border-char :rounded :top-left) "╭"))
   (is (equal (cl-tty.backend::border-char :rounded :horizontal) "─"))
   (is (equal (cl-tty.backend::border-char :rounded :vertical) "│"))
-  (is (equal (cl-tty.backend::border-char :rounded :bottom-right) "╯"))
+  (is (equal (cl-tty.backend::border-char :rounded :bottom-right) "╯")))
 
 (test border-char-double
   "modern-border-char returns double-line chars"
   (is (equal (cl-tty.backend::border-char :double :top-left) "╔"))
   (is (equal (cl-tty.backend::border-char :double :horizontal) "═"))
-  (is (equal (cl-tty.backend::border-char :double :vertical) "║"))
+  (is (equal (cl-tty.backend::border-char :double :vertical) "║")))
+
+(test suspend-resume-noop
+  "suspend-backend and resume-backend are no-ops in test context"
+  (let ((b (make-modern-backend)))
+    (is (null (multiple-value-list (suspend-backend b))))
+    (is (null (multiple-value-list (resume-backend b))))))