docs: port TUI roadmap to cl-tty, mark Emacs as secondary client

v0.8.0: Information Radiator now built on cl-tty v1.1.0. Minibuffer
uses cl-tty Dialog stack. New TODO items: conversation view (ScrollBox
+ Markdown), command palette (Select), sidebar (slot system), status bar
(Box + Theme), keybindings (keymap).

v0.9.1: Emacs is now an optional secondary client, not the primary
bridge. cl-tty is the primary TUI.

passepartout.asd

@@ -16,7 +16,7 @@
                (:file "lisp/core-pipeline")))
 
 (defsystem :passepartout/tui
-  :depends-on (:passepartout :croatoan :usocket :bordeaux-threads)
+  :depends-on (:passepartout :croatoan :cl-tty :usocket :bordeaux-threads)
   :serial t
   :components ((:file "lisp/channel-tui-state")
                (:file "lisp/channel-tui-view")