web: commit the in-progress UI polish as found in the working tree

Committed unchanged, by someone other than its author, so that the cluster UI
work that follows has a base to build on and can be reviewed separately: the
rewritten Overrides page (forms, validation, row-level state instead of
one-line handlers), the form and table clean-ups on Domains, Zones, Upstreams,
Settings and LocalZones, the AppShell fix that moves the shell inside the
identity provider, new nav labels, and the removal of the unused Kbd and
SectionTitle components and the Vite starter assets.

Login.tsx is deliberately not part of this: it belongs with the server-side OIDC
login work, which is still uncommitted, and stays in the working tree.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

web/src/pages/Zones.tsx

@@ -418,8 +418,8 @@ export default function Zones() {
   return (
     <div className="space-y-4">
       <PageHeader
-        title="Zones"
-        description="Local zones this resolver answers for itself, and the names it delegates elsewhere."
+        title="Managed zones"
+        description="Manage records and delegations for console-owned authoritative zones. Use Zone files to edit master-file data."
         actions={
           <div className="flex flex-wrap gap-2">
             <Button