input: total keyboard routing + per-terminal discipline (ADR 0006 ph1)

wm: FOCUSED is now a plain window id — window 0 (home terminal) is an
ordinary focusable window in the z-order.  The CONSOLE sentinel
(usize::MAX) and the focused()==0 special cases are gone; focus_console()
is an alias for focus(0).  Desktop clicks focus window 0.  The WM input
pump routes every key unconditionally: IRQ ring -> pump -> focused
window's owner; nothing polls the scancode rings directly any more.

tty: read_line() reads from the calling task's message queue (the old
global-ring read_line and the duplicate read_line_from_queue are merged);
raw mode (read_byte/try_read_byte) consumes the same queue;
interrupt_pressed drains the queue instead of the ring.

shell: task 0 owns home terminal window 0 and blocks on its queue like a
windowed shell; cat/hexdump stdin paths pass the home terminal handle.

sched: watchdog comments updated (shell parks on recv_blocking).

Verified in QEMU: F1 spawns terminals, F2 cycles focus home->term1->
term2, keystrokes land only in the focused window, ^C cancels a line,
edit runs raw over the queue and exits to a working prompt; test-disk
regression PASS.

1 files changed, 56 insertions, 0 deletions

diff --git a/scripts/test-focus.py b/scripts/test-focus.py
new file mode 100755
index 0000000..e1bbe2d
--- /dev/null
+++ b/scripts/test-focus.py
@@ -0,0 +1,56 @@
+#!/usr/bin/env python3
+"""Drive the focus-routing gate: 3 windows, type markers, verify routing.
+
+Connects to the QEMU monitor once and keeps the socket open (the per-call
+scripts/sendkeys.py pattern loses the socket when the monitor resets).
+
+Usage:  python3 scripts/test-focus.py /tmp/qmon.sock
+"""
+import socket
+import sys
+import time
+
+sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+sock.connect(sys.argv[1] if len(sys.argv) > 1 else "/tmp/sysboot-mon.sock")
+
+
+def sk(k, d=0.35):
+    sock.sendall(f"sendkey {k}\n".encode())
+    time.sleep(d)
+
+
+def line(txt, d=0.8):
+    for ch in txt:
+        if ch == " ":
+            sk("spc", 0.1)
+        elif ch.isupper():
+            sk("shift-" + ch.lower(), 0.12)
+        else:
+            sk(ch, 0.12)
+    sk("ret", d)
+
+
+time.sleep(0.5)
+
+# Home is focused at boot.
+line("windows")          # expect: home + nothing (or existing windows)
+time.sleep(1.5)
+
+# F1 -> term1 (focused on creation)
+sk("f1", 1.5)
+line("echo TERM1MARK")
+time.sleep(1.0)
+
+# F1 -> term2 (focused on creation)
+sk("f1", 1.5)
+line("echo TERM2MARK")
+time.sleep(1.0)
+
+# F2 cycles z-order: term2 -> term1
+sk("f2", 0.8)
+line("echo CYCLED")
+time.sleep(1.0)
+
+# F2 again: term1 -> home (window 0, oldest)
+sk("f2", 0.8)
+line("windows")