feat(axum): add safe html page composition

Add a SafeHtml PageRequest path for shell/partial composition and migrate examples so rendered hemplate fragments stay typed through the transport boundary instead of round-tripping through unchecked strings.

req: axum_integration/001

req: html_safety/001

req: html_safety/002

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, Handle, IntoEffect};
+use slhx_core::{BuildFingerprint, EffectBatch, Handle, IntoEffect, SafeHtml};
 use std::collections::BTreeMap;
 use std::convert::Infallible;
 
@@ -61,6 +61,17 @@ impl PageRequest {
             PageMode::Partial => PageResponse::partial(partial_html),
         }
     }
+
+    pub fn page_html(
+        self,
+        partial_html: SafeHtml,
+        shell: impl FnOnce(SafeHtml) -> SafeHtml,
+    ) -> PageResponse {
+        match self.mode {
+            PageMode::Full => PageResponse::full(shell(partial_html).into_string()),
+            PageMode::Partial => PageResponse::partial(partial_html.into_string()),
+        }
+    }
 }
 
 #[async_trait]