style(frontend): look&feel v2 — layered shadows, sharper radii, mono data register

Colors (GSD palette) untouched. New visual vocabulary across the whole GUI:
- warm-tinted layered shadow tokens (--shadow-xs/sm/md) replacing flat rings;
  cards/dialogs framed with hairline border + real elevation
- strict radii scale: xl cards / lg inputs / md controls / 2xl dialogs;
  buttons move from pills to rounded-md
- third type register: --font-mono + tabular-nums on SQL, timers, dates, ids;
  standardized .thot-label micro-label tier
- prose: framed tables with uppercase headers, elevated code blocks
- SqlViewer badges moved from hardcoded Tailwind greens/reds to success/
  destructive token tints; ResultsPanel inline styles replaced with classes
- artifact gate: first option rendered as filled primary action

Verified offline via Playwright against a mock backend replaying a real psd
session (no VPN needed). tsc clean, 115/115 vitest.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/src/widgets/SelectWidget.tsx

@@ -3,7 +3,7 @@ import { ReservedControls } from "./ReservedControls";
 
 export function SelectWidget({ descriptor, onRespond }: WidgetProps) {
   return (
-    <div className="space-y-4">
+    <div className="space-y-4 rounded-xl border border-border/70 bg-card p-4 shadow-sm">
       {(descriptor.title || descriptor.intro) && (
         <div className="space-y-1.5">
           {descriptor.title && (
@@ -27,7 +27,7 @@ export function SelectWidget({ descriptor, onRespond }: WidgetProps) {
           >
             <span>{o.label}</span>
             {o.recommended && (
-              <span className="shrink-0 rounded-full bg-[oklch(var(--success)/0.16)] px-2 py-0.5 text-[0.65rem] font-medium text-[oklch(0.5_0.13_165)]">
+              <span className="shrink-0 rounded-md bg-[oklch(var(--success)/0.16)] px-2 py-0.5 text-[0.65rem] font-medium text-[oklch(0.5_0.13_165)]">
                 consigliato
               </span>
             )}