feat: llimphi standalone — framework UI soberano extraído del monorepo

Motor gráfico Llimphi como workspace independiente: bucle Elm
(input→update→view→layout→raster→present) sobre wgpu+vello+taffy+parley.
Núcleo (hal/raster/layout/text/ui/theme/surface/motion/icons) + ~40 widgets
+ módulos, sin dependencias al resto del monorepo. cargo check --workspace
pasa (64 crates). Puerta de entrada: cargo run -p llimphi-ui --example counter.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

widgets/theme-switcher/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "llimphi-widget-theme-switcher"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+authors.workspace = true
+publish.workspace = true
+description = "llimphi-widget-theme-switcher — botón que cicla los presets de `llimphi_theme::Theme`. Análogo Llimphi del `nahual-widget-theme-switcher` GPUI: el caller lifta `Msg::ChangeTheme(Theme)` y reasigna el theme en su Model."
+
+[dependencies]
+llimphi-ui = { workspace = true }
+llimphi-theme = { workspace = true }
+
+[[example]]
+name = "theme_switcher_demo"
+path = "examples/theme_switcher_demo.rs"