refactor(saas): make navigation and status idiomatic

Use a real enhanceable Settings URL, remove response-simulated navigation, and replace the one-shot public SSE endpoint with an initial canonical event plus ongoing server-owned updates. Keep a bounded one-event probe for production-reference tests.

req: examples/014

req: nav/001

req: nav/002

req: nav/004

req: push/003

examples/saas/src/main.rs

@@ -5,14 +5,14 @@ use axum::middleware::{self, Next};
 use axum::response::{IntoResponse, Response};
 use axum::routing::{get, post};
 use axum::Router;
-use futures_util::stream;
+use futures_util::{stream, StreamExt};
 use hemx::IntoEffect;
 use hemx_axum::{runtime_js, runtime_js_path, sse, EffectResponse, InteractionRequest};
 use hemx_saas_example::{home_page, live_status, registry, settings_page, ui, AppContext};
 use std::collections::BTreeMap;
 use std::convert::Infallible;
 use std::path::PathBuf;
-use std::time::Instant;
+use std::time::{Duration, Instant};
 
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
@@ -81,16 +81,22 @@ async fn events(
     Query(params): Query<BTreeMap<String, String>>,
     State(ctx): State<AppContext>,
 ) -> impl IntoResponse {
-    let count = ctx.projects().len();
+    // The production reference exposes an ongoing server-owned stream; `once`
+    // keeps a bounded probe for package tests without changing the public path.
+    // req: examples/014
+    let event = |ctx: &AppContext| {
+        Ok::<_, Infallible>(live_status(ctx.projects().len()).into_batch(ui::BUILD_FINGERPRINT))
+    };
+    let initial = stream::once(std::future::ready(event(&ctx)));
     if params.contains_key("once") {
-        return sse(stream::iter([Ok::<_, Infallible>(
-            live_status(count).into_batch(ui::BUILD_FINGERPRINT),
-        )]));
+        return sse(initial.left_stream());
     }
 
-    sse(stream::iter([Ok::<_, Infallible>(
-        live_status(count).into_batch(ui::BUILD_FINGERPRINT),
-    )]))
+    let updates = stream::unfold(ctx, move |ctx| async move {
+        tokio::time::sleep(Duration::from_secs(15)).await;
+        Some((event(&ctx), ctx))
+    });
+    sse(initial.chain(updates).right_stream())
 }
 
 // req: auth/001 req: auth/002 req: auth/004