feat(style): generate checked class tokens

Add a boring CSS/SCSS class-token surface: slhx-build discovers static class tokens from hemplate/templates/stylesheets and emits generated CssClass constants. Add CssClasses for hemplate +class/view data and migrate techdemo dynamic/effect fragments toward hemplate-owned views with DOM-aware assertions.

req: style/001

req: style/002

req: style/003

req: html_safety/002

req: view/001

req: test/005

slhx/src/lib.rs

@@ -8,8 +8,8 @@ pub use slhx_derive::{app, component, handler, surface};
 
 pub mod prelude {
     pub use slhx_core::{
-        navigate, push, redirect, replace, Atom, BuildFingerprint, Effect, Form, Handle,
-        IntoEffect, KeyedSlot, Slot,
+        navigate, push, redirect, replace, Atom, BuildFingerprint, CssClass, CssClasses, Effect,
+        Form, Handle, IntoEffect, KeyedSlot, Slot,
     };
     pub use slhx_derive::{app, component, handler, surface};
 }