fix frontend board mapping, game-over handling, and WASM-4

- fix Xform yx and add a shared view-aware board_position helper
- add GTK automatic game-over, restart, status, and multi-capture selection
- pin librsvg to the 2.60 series to match GTK4/glib 0.20
- add WASM orientation, undo/redo/new/flip controls, and winner overlay
- replace WASM crown images with canvas paths and remove dead files/deps
- make WASM-4 playable with mouse input, crowns, winner handling, and correct mapping
- move the WASM-4 release profile to the workspace root
- clean up frontend dead code and update the README

Cargo.toml

@@ -25,16 +25,14 @@ rust-version = "1.87"
 [workspace.dependencies]
 rdraught = { path = "rdraught", version = "0.1" }
 rdraught-ui-common = { path = "rdraught-ui-common", version = "0.1" }
-base64 = "0.22"
 cairo-rs = "0.20"
 cairo-sys-rs = "0.20"
-librsvg = "2.60"
+librsvg = "~2.60"
 gtk4 = {version = "0.9", features = ["v4_10"] }
 gdk4 = "0.9"
 gio = "0.20"
 glib = "0.20"
 wasm4 = "0.2"
-wasm4-sys = "0.1"
 strum = "0.27"
 strum_macros = "0.27"
 heapless = "0.8"
@@ -44,3 +42,9 @@ console_error_panic_hook = "0.1"
 sdl3 = { version = "0.14.35" }
 sdl3-sys = { version = "0.5" }
 rmath = {version = "0.1.0", registry = "gitea"}
+
+[profile.release]
+lto = true
+
+[profile.release.package.rdraught-w4]
+opt-level = "z"