The mouse-event struct was already in cl-tty.input. All mouse handling
logic (mouse-mixin, hit-test, selection, clipboard, link detection)
was in a separate cl-tty.mouse package. Moved everything into the
input package where the struct lives, eliminating one package boundary.
Changes:
- absorb mouse-mixin, handle-mouse-event, hit-test, selection struct,
selection variables/functions, cell-link-at, open-link-at into
text-input.org (tangled to input.lisp)
- update cl-tty.input defpackage with mouse exports
- mouse tests merged into INPUT-SUITE (appended to input-tests.lisp)
- delete mouse.org, mouse-package.lisp, mouse.lisp, mouse-tests.lisp
- update ASDF, run-all-tests.lisp, scripts to drop mouse references
All test suites pass at 100% (INPUT-SUITE: 102 tests, +6 from mouse)