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, 72 insertions, 0 deletions

diff --git a/rsapi/src/lib.rs b/rsapi/src/lib.rs
index dfe75d6..e5f2119 100644
--- a/rsapi/src/lib.rs
+++ b/rsapi/src/lib.rs
@@ -105,6 +105,66 @@ pub struct PciDevice {
     pub device_id: u16,
 }
 
+// ---- GUI types (v2 window/event) ----
+
+/// Window buffer info returned by wm_buffer.
+#[repr(C)]
+#[derive(Clone, Copy)]
+pub struct WindowInfo {
+    pub ptr: *mut u32,
+    pub w: u32,
+    pub h: u32,
+}
+
+/// Key event kind (flattened for ABI stability).
+#[repr(u8)]
+#[derive(Clone, Copy, PartialEq, Eq)]
+pub enum WmKeyKind {
+    Char = 0,
+    Enter = 1,
+    Backspace = 2,
+    Tab = 3,
+    Escape = 4,
+    CtrlC = 5,
+    ArrowUp = 10,
+    ArrowDown = 11,
+    ArrowLeft = 12,
+    ArrowRight = 13,
+    Home = 14,
+    End = 15,
+    PageUp = 16,
+    PageDown = 17,
+    Delete = 18,
+    F1 = 20,
+    F2 = 21,
+    F3 = 22,
+    F4 = 23,
+    Unknown = 255,
+}
+
+/// Mouse button state.
+#[repr(C)]
+#[derive(Clone, Copy)]
+pub struct WmMouseEvent {
+    pub x: i32,
+    pub y: i32,
+    pub buttons: u8,
+}
+
+/// One window manager event delivered to a GUI binary.
+#[repr(C)]
+#[derive(Clone, Copy)]
+pub struct WmEvent {
+    pub kind: u8, // 0=key, 1=mouse, 2=focus, 3=close
+    pub key_kind: WmKeyKind,
+    pub key_char: u8,
+    pub mouse: WmMouseEvent,
+    pub focused: bool,
+    pub _pad: [u8; 4],
+}
+
+
+
 /// Kernel version information.
 #[derive(Clone, Copy)]
 pub struct KernelVersion {
@@ -167,4 +227,16 @@ pub struct Exports {
     pub klog_dump: fn(buf: *mut u8, cap: u64) -> u64,
     /// Fill `out` with kernel version info.
     pub kernel_version: fn(out: &mut KernelVersion),
+
+    // ---- window/events (v2 GUI) ----
+    /// Create a window; returns window id or -1.
+    pub wm_create: fn(title: Line, w: u32, h: u32) -> i32,
+    /// Get the window's pixel buffer info.
+    pub wm_buffer: fn(id: i32, out: &mut WindowInfo) -> bool,
+    /// Composite the window to screen.
+    pub wm_flush: fn(id: i32),
+    /// Destroy a window.
+    pub wm_destroy: fn(id: i32),
+    /// Non-blocking: receive one event. Returns true if an event was delivered.
+    pub wm_recv: fn(out: &mut WmEvent) -> bool,
 }