GUI: window/event exports, paint binary, event-loop gate

rsapi: WmEvent (kind=u8 enum: 0=key, 1=mouse, 2=focus, 3=close),
WmKeyKind (Char/Enter/Backspace/F1-F4/…), WmMouseEvent (x/y/buttons),
WindowInfo (ptr/w/h).  Five new exports: wm_create, wm_buffer,
wm_flush, wm_destroy, wm_recv (non-blocking TaskMsg dispatch → WmEvent).

Shell: abi_wm_* wrappers bridge rsapi types to rsnix::wm and
sched::recv(); wm_recv translates TaskMsg::Key/Mouse/Focus/Close
into flat WmEvent union.

bins/paint: gate binary — create_window + buffer + event loop with
Bresenham line drawing, color select (1-8), clear (c), F4 close.
All via wm_* ABI exports.

Fully migrated: date, mem, pci, cat, ls, mkdir, touch, rm, klog,
info, paint (11 external binaries in /bin/cli/ + 3 gate binaries).

1 files changed, 7 insertions, 0 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 35ac614..a4accd7 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -73,6 +73,13 @@ dependencies = [
 ]
 
 [[package]]
+name = "paint"
+version = "0.6.0"
+dependencies = [
+ "rsapi",
+]
+
+[[package]]
 name = "pci"
 version = "0.6.0"
 dependencies = [