Frontend redesign chunk 6: Live view

New components/LiveView.tsx renders the default landing at "/": full-bleed
MapView (rail + legend from chunk 5) plus a new TimeScrubber strip below
it — real call-density bars over the selected 1h/6h/24h/7d window, tinted
by the worst severity in each bucket, playhead pinned to NOW. The playhead
doesn't scrub yet; that needs `resolved_at` on incidents, which doesn't
exist server-side (blocked chunk 13, in DEFERRED.md) — the density data
itself is live, not a fixture.

Distinguishes the two empty states UI_REDESIGN.md §4 calls out: a
configured-but-quiet org (nodes online, zero active incidents) now shows
"Listening — last check-in Xm ago" instead of rendering nothing, separate
from the zero-node case (chunk 10's Activation screen).

app/page.tsx's HomePage now renders LiveView directly for a signed-in,
provisioned user instead of the chunk-4 interim redirect to /incidents.

Per UI_REDESIGN.md chunk 6.

drb-frontend/app/page.tsx

@@ -1,13 +1,12 @@
 "use client";
 
-import { useEffect } from "react";
 import Link from "next/link";
-import { useRouter } from "next/navigation";
 import { LinkButton } from "@/components/ui/Button";
 import { Card } from "@/components/ui/Card";
 import { Badge } from "@/components/ui/Badge";
 import { PLANS } from "@/lib/billing";
 import { useAuth } from "@/components/AuthProvider";
+import { LiveView } from "@/components/LiveView";
 
 const CAPABILITIES = [
   {
@@ -147,21 +146,15 @@ function MarketingHomePage() {
 
 /**
  * "/" is marketing for a signed-out visitor and Live (the map) for anyone
- * signed in — see UI_REDESIGN.md §3, "the map is the home screen". The Live
- * screen itself lands in chunk 6; until then a signed-in, provisioned user
- * is sent to /incidents rather than shown stale marketing copy. A user with
- * no org_id yet still sees marketing (unchanged — that's the pre-redesign
- * behaviour for an unprovisioned account, out of scope here).
+ * signed in — see UI_REDESIGN.md §3, "the map is the home screen". A user
+ * with no org_id yet still sees marketing (unchanged — that's the
+ * pre-redesign behaviour for an unprovisioned account, out of scope here;
+ * ChromeSwitcher's own no-claim guard only fires off marketing paths).
  */
 export default function HomePage() {
   const { user, loading, orgId } = useAuth();
-  const router = useRouter();
 
-  useEffect(() => {
-    if (loading || !user || !orgId) return;
-    router.replace("/incidents");
-  }, [loading, user, orgId, router]);
-
-  if (loading || (user && orgId)) return null;
+  if (loading) return null;
+  if (user && orgId) return <LiveView />;
   return <MarketingHomePage />;
 }

drb-frontend/components/LiveView.tsx

@@ -0,0 +1,79 @@
+"use client";
+
+/**
+ * Live — the default landing for every authenticated user (UI_REDESIGN.md
+ * §3, §5.1). Full-bleed map with the incident rail/legend MapView already
+ * renders (chunk 5), plus a time-density scrubber strip below it.
+ */
+import { useEffect, useState } from "react";
+import dynamic from "next/dynamic";
+import { useNodes } from "@/lib/useNodes";
+import { useActiveCalls, useCalls } from "@/lib/useCalls";
+import { useActiveIncidents } from "@/lib/useIncidents";
+import { TimeScrubber } from "@/components/TimeScrubber";
+
+const MapView = dynamic(() => import("@/components/MapView"), { ssr: false });
+
+function timeAgo(date: Date): string {
+  const s = Math.floor((Date.now() - date.getTime()) / 1000);
+  if (s < 60) return `${s}s ago`;
+  if (s < 3600) return `${Math.floor(s / 60)}m ago`;
+  return `${Math.floor(s / 3600)}h ago`;
+}
+
+export function LiveView() {
+  const { nodes, loading: nodesLoading } = useNodes();
+  const activeCalls = useActiveCalls();
+  const activeIncidents = useActiveIncidents();
+  // Wide-ish recent window: feeds both the incident-path polyline (chunk 5)
+  // and the scrubber's density bars. Not a fixture — real recent calls.
+  const { calls: recentCalls, loading: callsLoading } = useCalls(500);
+  const [lastUpdated, setLastUpdated] = useState<Date | null>(null);
+
+  useEffect(() => {
+    if (!nodesLoading) setLastUpdated(new Date());
+  }, [nodes, activeCalls, activeIncidents, nodesLoading]);
+
+  const configuredButQuiet = !nodesLoading && nodes.length > 0 && activeIncidents.length === 0;
+  const mostRecentSeen = configuredButQuiet
+    ? nodes
+        .map((n) => n.last_seen)
+        .filter((s): s is string => !!s)
+        .sort()
+        .at(-1)
+    : null;
+
+  return (
+    <div className="flex flex-col h-full">
+      <div className="relative flex-1 min-h-0">
+        {nodesLoading || callsLoading ? (
+          <div className="w-full h-full flex items-center justify-center text-ink-muted text-sm">
+            Loading map…
+          </div>
+        ) : (
+          <MapView
+            nodes={nodes}
+            activeCalls={activeCalls}
+            incidents={activeIncidents}
+            calls={recentCalls}
+            lastUpdated={lastUpdated}
+          />
+        )}
+
+        {/* Configured-and-quiet — distinct from "no nodes at all" (chunk 10's
+            Activation screen handles the zero-node case). A node that's
+            online but has heard nothing is NOT the same empty state as an
+            org with no equipment. */}
+        {configuredButQuiet && (
+          <div className="absolute top-12 left-1/2 -translate-x-1/2 z-[1001] pointer-events-none">
+            <span className="bg-surface/90 border border-line rounded-full px-3 py-1 text-xs text-ink-2 whitespace-nowrap">
+              ● Listening{mostRecentSeen ? ` — last check-in ${timeAgo(new Date(mostRecentSeen))}` : ""}
+            </span>
+          </div>
+        )}
+      </div>
+
+      <TimeScrubber calls={recentCalls} />
+    </div>
+  );
+}

drb-frontend/components/TimeScrubber.tsx

@@ -0,0 +1,91 @@
+"use client";
+
+/**
+ * Live's time scrubber — call-density bars over the selected window, tinted
+ * by the worst severity in each bucket, playhead pinned to NOW. Range
+ * presets change which window is densitized; the playhead itself does not
+ * move in this build — history scrub needs `resolved_at` on incidents,
+ * which doesn't exist yet (UI_REDESIGN.md chunk 13, blocked on backend,
+ * tracked in DEFERRED.md). This is real call density from live data, not a
+ * fixture — only the scrub interaction is deferred.
+ */
+import { useMemo, useState } from "react";
+import type { CallRecord } from "@/lib/types";
+import { SEVERITY_COLORS, severityRank } from "@/lib/severity";
+
+const RANGES = [
+  { label: "1h", ms: 60 * 60 * 1000 },
+  { label: "6h", ms: 6 * 60 * 60 * 1000 },
+  { label: "24h", ms: 24 * 60 * 60 * 1000 },
+  { label: "7d", ms: 7 * 24 * 60 * 60 * 1000 },
+] as const;
+
+const BUCKETS = 48;
+
+export function TimeScrubber({ calls }: { calls: CallRecord[] }) {
+  const [rangeIdx, setRangeIdx] = useState(2); // default 24h
+
+  const range = RANGES[rangeIdx];
+
+  const buckets = useMemo(() => {
+    const now = Date.now();
+    const start = now - range.ms;
+    const bucketMs = range.ms / BUCKETS;
+    const counts = Array.from({ length: BUCKETS }, () => ({ count: 0, worstRank: -1 }));
+    for (const c of calls) {
+      const t = new Date(c.started_at).getTime();
+      if (Number.isNaN(t) || t < start || t > now) continue;
+      const idx = Math.min(BUCKETS - 1, Math.floor((t - start) / bucketMs));
+      counts[idx].count += 1;
+      const rank = severityRank(c.severity);
+      if (rank > counts[idx].worstRank) counts[idx].worstRank = rank;
+    }
+    return counts;
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [calls, rangeIdx]);
+
+  const maxCount = Math.max(1, ...buckets.map((b) => b.count));
+
+  return (
+    <div className="h-[84px] bg-surface/90 border-t border-line px-4 flex items-center gap-4">
+      <div className="flex-1 h-12 flex items-end gap-[2px]">
+        {buckets.map((b, i) => {
+          const heightPct = b.count === 0 ? 4 : Math.max(10, (b.count / maxCount) * 100);
+          const color =
+            b.worstRank === 3
+              ? SEVERITY_COLORS.major
+              : b.worstRank === 2
+              ? SEVERITY_COLORS.moderate
+              : b.worstRank >= 0
+              ? "var(--ink-2)"
+              : "var(--line-strong)";
+          return (
+            <div
+              key={i}
+              title={b.count > 0 ? `${b.count} call${b.count !== 1 ? "s" : ""}` : undefined}
+              style={{ height: `${heightPct}%`, background: color, flex: 1, borderRadius: 1, minWidth: 2 }}
+            />
+          );
+        })}
+        {/* Playhead — pinned to NOW; doesn't move yet (see file header) */}
+        <div className="relative w-0">
+          <div className="absolute right-0 -top-14 bottom-0 w-[2px] bg-accent" />
+        </div>
+      </div>
+      <div className="flex items-center gap-1 shrink-0">
+        {RANGES.map((r, i) => (
+          <button
+            key={r.label}
+            onClick={() => setRangeIdx(i)}
+            className={`px-2 py-1 rounded text-xs font-mono transition-colors ${
+              i === rangeIdx ? "bg-accent text-white" : "text-ink-muted hover:text-ink-2"
+            }`}
+          >
+            {r.label}
+          </button>
+        ))}
+        <span className="ml-2 text-xs text-ink-muted font-mono">NOW</span>
+      </div>
+    </div>
+  );
+}