fix(water-admin): rebrand subtitle to "Tuxedo Field Operations"

The header subtitle was "Signed in as Admin" — appended with a
literal "Admin" suffix. Customers misread it as "every user is an
admin" because the page doesn't know *which* admin is signed in
(the wl_admin_session cookie is an opaque bearer token with no
user identity).

Replace the label value with "Tuxedo Field Operations" /
"Operaciones de Campo Tuxedo" so the page frames itself as a
brand-internal operations tool, not a per-user role. Also drops
the trailing " Admin" suffix from the rendered string.

The /water (irrigator) page is unchanged — it still shows the
actual irrigator name since wl_session is keyed to a real user.

src/components/water/WaterAdminClient.tsx

@@ -30,7 +30,7 @@ type Props = {
 const LABELS = {
   en: {
     title: "Water Log Admin",
-    loggedInAs: "Signed in as",
+    loggedInAs: "Tuxedo Field Operations",
     logout: "Sign out",
     recentEntries: "Recent Entries",
     noEntries: "No entries yet",
@@ -89,7 +89,7 @@ const LABELS = {
   },
   es: {
     title: "Administración del Registro de Agua",
-    loggedInAs: "Conectado como",
+    loggedInAs: "Operaciones de Campo Tuxedo",
     logout: "Salir",
     recentEntries: "Entradas recientes",
     noEntries: "Sin entradas aún",
@@ -1296,7 +1296,7 @@ export default function WaterAdminClient({
     <main className="min-h-screen bg-zinc-950 text-zinc-100">
       <AdminHeader
         title={t.title}
-        subtitle={`${t.loggedInAs} Admin`}
+        subtitle={t.loggedInAs}
         lang={state.lang}
         onChangeLang={handleChangeLang}
         onLogout={handleLogout}