chore: sync the frontend template from a0fbafb to 5434760

Carries eight template commits: the provider sandbox actually running, release
admission to a named environment, the product feature manifest with its runtime
kill switch, architecture and documentation rules that match what is enforced,
the removability fixtures, and the browser, visual and performance evidence.

Product identity is unchanged. `package.json` keeps `tech-log-frontend` and the
catalog keeps the Tech Log naming; the home page was not in the delta. The
visual baselines are this product's own — the template's were excluded from the
transplant and these were regenerated here, where the only difference is the
platform overview's new product-feature section.

What this repository gains operationally: `config/runtime/{local,development,
staging,production}.json` with `FE-GATE-027` refusing an artifact whose runtime
document does not match the environment it is being admitted to, and
`FEATURE_OVERRIDES` for taking an installed feature out of service without a
rebuild.

Verified here: eight gates green, build green, visual 5/5, and 1,858 of 1,859
tests in the suites that do not need a sandbox — the one failure passes in
isolation and is a jsdom lazy-chunk timeout under parallel load. The provider
suites cannot run on this machine at all: `kernel.apparmor_restrict_unprivileged
_userns=1` makes `bwrap --unshare-net` fail, reproducible without any code from
either repository.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/presentation/routes/app-router.tsx

@@ -18,6 +18,7 @@ import {
 
 import {
   getRoute,
+  ROUTE_FEATURE_OWNER,
   ROUTE_REGISTRY,
 } from "../../features/installed-feature-contracts.ts";
 import type { RouteDefinition } from "../../contracts/routes.ts";
@@ -96,6 +97,26 @@ function InvalidRouteSurface({ code }: { code: string }) {
   );
 }
 
+/**
+ * §3.5. A route whose feature the runtime document switched off. It answers as
+ * "not available" rather than rendering the feature or crashing, so disabling a
+ * feature is a deployment action and not an outage.
+ */
+function DisabledFeatureSurface({ featureId }: { featureId: string }) {
+  const { message } = useLocale();
+  return (
+    <section className="ui-page" data-surface="disabled-feature">
+      <PageHeader
+        title={message("route.disabledFeature.title")}
+        description={message("route.disabledFeature.description")}
+      />
+      <p data-disabled-feature={featureId}>
+        {message("route.disabledFeature.action")}
+      </p>
+    </section>
+  );
+}
+
 function RouteLifecycle({
   definition,
   buildId,
@@ -245,11 +266,22 @@ function RegisteredRoute({
   buildId: string;
 }) {
   const definition = getRoute(routeId);
-  const runtime = ROUTE_RUNTIME[routeId];
   const params = useParams();
   const [search] = useSearchParams();
   const location = useLocation();
-  const { diagnostics, recovery } = useApplication();
+  const { diagnostics, runtime: platformRuntime, recovery } = useApplication();
+  // §3.5. A feature the runtime document disabled is out of service, not
+  // merely hidden: withdrawing it from navigation alone would leave a typed
+  // deep link that still mounts it.
+  const owner = ROUTE_FEATURE_OWNER[routeId];
+  if (owner !== undefined && !platformRuntime.isFeatureActive(owner)) {
+    return <DisabledFeatureSurface featureId={owner} />;
+  }
+  // The registry and the runtime table are composed from the same manifest, so
+  // a route without a component means the two disagree — refuse rather than
+  // crash the shell.
+  const runtime = ROUTE_RUNTIME[routeId];
+  if (!runtime) return <DisabledFeatureSurface featureId={owner ?? routeId} />;
   const parsed = parseRouteInput(routeId, params, search);
   if (!parsed.success) return <InvalidRouteSurface code={parsed.code} />;