fix(web-ui): remove Capture nav item, add Playout testing warning

Remove 'Capture' from the Operations nav section in shell.jsx — users
configure recorders via the Recorders page; the Capture route/component
is left intact for any remaining references.

Also remove 'capture' from the ingest open-group list (it was listed
as an ingest child despite living in Operations, now moot).

Add a prominent amber warning banner at the top of the Playout page
body (screens-playout.jsx) to make clear the feature is in testing and
not ready for production use.

No cherry-pick from fix/library-and-signal-indicator — all commits on
that branch are already present on main.

services/web-ui/public/screens-playout.jsx

@@ -1147,6 +1147,21 @@ function Playout() {
       </div>
 
       <div className="page-body po-page">
+        <div style={{
+          background: '#fef3c7',
+          borderLeft: '4px solid #f59e0b',
+          color: '#78350f',
+          padding: '10px 16px',
+          fontWeight: 600,
+          fontSize: 14,
+          borderRadius: 4,
+          marginBottom: 12,
+          display: 'flex',
+          alignItems: 'center',
+          gap: 8,
+        }}>
+          ⚠ Playout is in testing — not for production use.
+        </div>
         {err && <div className="alert error">{err}</div>}
 
         {channels === null && <div className="muted">Loading channels…</div>}

services/web-ui/public/shell.jsx

@@ -27,7 +27,6 @@ const NAV_SECTIONS = [
   {
     label: "Operations",
     items: [
-      { id: "capture", label: "Capture", icon: "capture" },
       { id: "playout", label: "Playout", icon: "signal" },
       { id: "jobs", label: "Jobs", icon: "jobs" },
     ],
@@ -150,7 +149,7 @@ function Sidebar({ active, onNavigate, me, collapsed, onToggle }) {
   };
 
   React.useEffect(() => {
-    const ingestChildren = ["upload", "youtube", "recorders", "schedule", "capture", "monitors"];
+    const ingestChildren = ["upload", "youtube", "recorders", "schedule", "monitors"];
     if (ingestChildren.includes(active)) {
       setOpenGroups(prev => prev.has("ingest") ? prev : new Set([...prev, "ingest"]));
     }