feat(axum): register checked handles

Add HandlerRegistry::register_handle for generated Handle<T> values and migrate examples away from passing raw numeric handle ids at registration sites.

req: ceremony/004

req: public_api/001

slhx-axum/src/lib.rs

@@ -5,7 +5,7 @@ use axum::http::{header, request::Parts, HeaderMap, HeaderValue, Request, Respon
 use axum::response::sse::{Event, Sse};
 use axum::response::IntoResponse;
 use futures_util::{Stream, StreamExt};
-use slhx_core::{BuildFingerprint, EffectBatch, IntoEffect};
+use slhx_core::{BuildFingerprint, EffectBatch, Handle, IntoEffect};
 use std::collections::BTreeMap;
 use std::convert::Infallible;
 
@@ -262,6 +262,17 @@ impl HandlerRegistry {
         self
     }
 
+    pub fn register_handle<I, E>(
+        self,
+        handle: Handle<I>,
+        handler: impl Fn(InteractionForm) -> E + Send + Sync + 'static,
+    ) -> Self
+    where
+        E: IntoEffect,
+    {
+        self.register(handle.id().id, handler)
+    }
+
     pub fn dispatch(&self, form: InteractionForm) -> Result<EffectResponse, DispatchRejection> {
         let handle_id = form.handle_id;
         let Some(handler) = self.handlers.get(&handle_id) else {