feat(web): make Web UI responsive for mobile

- Nav: icons only on mobile, icon+label on sm+
- Brand: abbreviated "H A" on mobile, full "Hermes Agent" on sm+
- Content: reduced padding on mobile (px-3 vs px-6)
- StatusPage: session cards stack vertically on mobile, truncate
  overflow text, strip model namespace for brevity
- ConfigPage: sidebar becomes horizontal scrollable pills on mobile
  instead of fixed left column, search hidden on mobile
- SessionsPage: title + search stack vertically on mobile, search
  goes full-width
- Card component: add overflow-hidden to prevent content bleed
- Body/root: add overflow-x-hidden to prevent horizontal scroll
- Footer: reduced font sizes on mobile

All changes use Tailwind responsive breakpoints (sm: prefix).
No logic changes — purely layout/CSS adjustments.

web/src/pages/SessionsPage.tsx

@@ -227,7 +227,7 @@ function SessionRow({
               )}
             </div>
             <div className="flex items-center gap-1.5 text-xs text-muted-foreground">
-              <span className="truncate max-w-[180px]">{(session.model ?? "unknown").split("/").pop()}</span>
+              <span className="truncate max-w-[120px] sm:max-w-[180px]">{(session.model ?? "unknown").split("/").pop()}</span>
               <span className="text-border">&#183;</span>
               <span>{session.message_count} msgs</span>
               {session.tool_call_count > 0 && (
@@ -374,7 +374,7 @@ export default function SessionsPage() {
   return (
     <div className="flex flex-col gap-4">
       {/* Header outside card for lighter feel */}
-      <div className="flex items-center justify-between">
+      <div className="flex flex-col sm:flex-row sm:items-center gap-2 sm:justify-between">
         <div className="flex items-center gap-2">
           <MessageSquare className="h-5 w-5 text-muted-foreground" />
           <h1 className="text-base font-semibold">Sessions</h1>
@@ -382,7 +382,7 @@ export default function SessionsPage() {
             {total}
           </Badge>
         </div>
-        <div className="relative w-64">
+        <div className="relative w-full sm:w-64">
           {searching ? (
             <div className="absolute left-2.5 top-1/2 -translate-y-1/2 h-3.5 w-3.5 animate-spin rounded-full border-[1.5px] border-primary border-t-transparent" />
           ) : (