Windowed GUI: wm module, input routing, and the paint app

- Add the wm window-manager facility per ADR 0004: overlapping
  pixel-surface windows, damage-rectangle compositing, WM-drawn title
  bar, focus/minimize/close, and F1-F4 keybindings
- Add gop shadow compositing primitives and vt::repaint_region so the
  console stays layer 0 beneath windows
- Route mouse (absolute coords, press/release edges) and keyboard
  (focus-aware input pump) to the focused window
- Add the rspaint drawing-program crate (pen, 8 colors, clear) and shell
  draw/windows/restore commands
- Extend TaskMsg with AppMouse/Focus/Close and document the design in
  CONTEXT.md + ADR 0004

1 files changed, 10 insertions, 0 deletions

diff --git a/rspaint/Cargo.toml b/rspaint/Cargo.toml
new file mode 100644
index 0000000..66364a2
--- /dev/null
+++ b/rspaint/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "rspaint"
+version = "0.1.0"
+edition = "2024"
+
+[lints]
+workspace = true
+
+[dependencies]
+rsnix = { path = "../rsnix" }