v4.1.0: add the egui workspace member and the roulette style spike

Phase 3 of the GUI plan. gui/ is a separate package that depends on the core with default features off, so egui never enters the TUI or server build graph. It carries the theme tokens and two embedded fonts (Open Sans OFL, Hack MIT), paints the felt, chips, cursor and wheel from RouletteView, and composes the persistent header with the betting sidebar.

The reference screen runs on demo state: arrow keys move the shared Cursor, clicks place chips, and SPIN animates a 2.4 s wheel that settles with the winning pocket under the pointer. No network until Phase 4.

Verified x86_64-pc-windows-gnu cross-compile. Measured on Linux at 1080p with llvmpipe: 6.0 MB binary (4.7 MB on Windows), 52 ms to window, 137 MB idle RSS, 0% idle CPU.

1 files changed, 21 insertions, 0 deletions

diff --git a/gui/Cargo.toml b/gui/Cargo.toml
new file mode 100644
index 0000000..a2f4154
--- /dev/null
+++ b/gui/Cargo.toml
@@ -0,0 +1,21 @@
+[package]
+name = "zagan-bet-gui"
+version = "4.1.0"
+edition = "2024"
+license = "GPL-3.0-or-later"
+description = "Desktop frontend for zagan-bet"
+
+[[bin]]
+name = "zagan-bet-gui"
+path = "src/main.rs"
+
+[dependencies]
+# No default features: the GUI never links the server's native-tls.
+zagan-bet = { path = "..", default-features = false }
+# glow (OpenGL) rather than wgpu: no Vulkan runtime, and it cross-compiles to
+# Windows with the mingw toolchain. Fonts are embedded, so no default_fonts.
+eframe = { version = "0.37", default-features = false, features = [
+    "glow",
+    "wayland",
+    "x11",
+] }