Give the nav's dead links somewhere to land

Three of the app's routes were referenced but never existed, so the redesign's
navigation pointed at 404s from several directions.

/dashboard was the post-login and fallback redirect target in nine places --
login, onboarding, middleware, the admin/nodes/systems/tokens/settings guards,
and the marketing header -- but app/dashboard/ was never created. Signing in
normally dropped the user on a 404. The real signed-in home is "/", which
app/page.tsx already renders as LiveView for an authed user with an org, and
which the nav labels "Live"; all nine now point there.

Nav also linked /watch and /network, neither of which existed. /watch is the
alerts screen under its redesign name, so it re-exports app/alerts/page.tsx
and /alerts stays reachable for old links. /network is new: the "my equipment"
hub the redesign moved /nodes, /systems and /tokens behind and then never
built, which had left /systems and /tokens with no entry point in the UI at
all. Its hooks all run before the admin/operator guard, per d041c86.

Separately, the admin page's guard read isAdmin without authLoading, so every
cold load of /admin -- typed URL, hard refresh, bookmark -- redirected away
while the Firebase claims were still resolving. Admin was only reachable by
clicking through from an already-mounted page. Now it waits, like every other
guarded route does.

And /incidents no longer lies about an empty list: a failed Firestore query
leaves `incidents` empty just as a quiet night does, and the page was printing
"No incidents recorded yet" over the top of a missing-composite-index error.
useIncidents already returned `error`; the page just ignored it. It now renders
an ErrorBanner instead, so the undeployed indexes in server-26#13 read as a
failure rather than as silence on the radio.

Closes server-26#30, server-26#31. server-26#13 stays open -- the rules and
indexes still have to be pushed to the live project by hand.

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

drb-frontend/app/incidents/page.tsx

@@ -10,7 +10,7 @@ import type { IncidentRecord } from "@/lib/types";
 import { PageHeader } from "@/components/ui/PageHeader";
 import { Button } from "@/components/ui/Button";
 import { Badge } from "@/components/ui/Badge";
-import { EmptyState } from "@/components/ui/EmptyState";
+import { EmptyState, ErrorBanner } from "@/components/ui/EmptyState";
 import { SkeletonCard } from "@/components/ui/Skeleton";
 import { isKnownSeverity, severityRank } from "@/lib/severity";
 import { SeverityMark, SeveritySpine } from "@/components/marks/SeverityMark";
@@ -166,7 +166,7 @@ function CreateModal({ onClose, onCreate }: { onClose: () => void; onCreate: (bo
 
 export default function IncidentsPage() {
   const { isAdmin } = useAuth();
-  const { incidents, loading } = useIncidents();
+  const { incidents, loading, error } = useIncidents();
   const activeCalls = useActiveCalls();
   const [showCreate, setShowCreate] = useState(false);
   const [severityFilter, setSeverityFilter] = useState<SeverityFilter>("all");
@@ -275,7 +275,16 @@ export default function IncidentsPage() {
             </section>
           ))}
 
-          {filtered.length === 0 && (
+          {/* An empty list is only news when the query actually succeeded.
+              A failed Firestore query (missing composite index, denied rules)
+              also leaves `incidents` empty, and rendering "no incidents
+              recorded yet" over the top of it told the operator the radio was
+              quiet when the page had simply failed to load — server-26#13. */}
+          {filtered.length === 0 && error && (
+            <ErrorBanner message={`Couldn't load incidents: ${error}`} />
+          )}
+
+          {filtered.length === 0 && !error && (
             <EmptyState
               title={incidents.length === 0 ? "No incidents recorded yet" : "No incidents match this filter"}
               description={