X on the console: /dev/tty0, a palette, and startx that works

Xorg finds its VT through /dev/tty0, and without one ran on none: the
console went on drawing into the framebuffer over the X screen. tty0 is
the terminal on screen, as on Linux. FBIOPUTCMAP succeeds, as it does on
a true-colour Linux framebuffer, instead of 256 logged errors per start.

schos-base gives root a .xserverrc with -dumbSched, Xorg's switch for
input on the main loop: SchOS has no threads, and Xorg crashed in
pthread_join on its input thread when the first client left. It adds
the hostname to /etc/hosts, so xauth can resolve schos:0.

zsh loses PROMPT_SP: on a serial terminal narrower than the console its
padding wrapped and left a # above every prompt. bootcheck knows zsh's
prompt and matches without colour codes, so busybox's ls reads as text.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01S1giNvrHTrPMPw7V6x1kQ4

kernel/fs/devfs.c

@@ -83,6 +83,11 @@ static const struct devnode devnodes[] = {
      was one terminal. Minor 10 resolves through proc->ctty; see
      vt_for_minor() in kernel/core/console.c. */
   { "tty",     1, 10, D_ROOT },
+  /* The terminal on screen, as on Linux. Xorg opens it to find a free VT and
+     switch to it, and without one ran on no VT at all: the console went on
+     drawing into the framebuffer over the X screen. Any minor that is not a
+     numbered terminal or the controlling one resolves to vt_current(). */
+  { "tty0",    1, 0,  D_ROOT },
   { "tty1",    1, 11, D_ROOT },
   { "tty2",    1, 12, D_ROOT },
   { "tty3",    1, 13, D_ROOT },