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/FreetextWidget.tsx

@@ -4,20 +4,20 @@ import type { WidgetProps } from "./types";
 export function FreetextWidget({ descriptor, onRespond }: WidgetProps) {
   const [text, setText] = useState("");
   return (
-    <div className="space-y-3">
+    <div className="space-y-3 rounded-xl border border-border/70 bg-card p-4 shadow-sm">
       {descriptor.title && (
         <p className="text-[0.95rem] font-semibold leading-snug text-foreground">
           {descriptor.title}
         </p>
       )}
       <textarea
-        className="min-h-24 w-full resize-y rounded-lg border border-input bg-card p-3 text-sm outline-none transition-colors focus:border-primary/40 focus:ring-2 focus:ring-ring/20"
+        className="min-h-24 w-full resize-y rounded-lg border border-input bg-card p-3 text-sm shadow-xs outline-none transition-[border-color,box-shadow] focus:border-primary/50 focus:ring-2 focus:ring-ring/20"
         value={text}
         onChange={(e) => setText(e.target.value)}
         placeholder="Type your answer…"
       />
       <button
-        className="rounded-lg bg-primary px-4 py-2 text-sm font-medium text-primary-foreground transition-colors hover:bg-[oklch(var(--primary-hover))]"
+        className="rounded-md bg-primary px-4 py-2 text-sm font-semibold text-primary-foreground shadow-xs transition-colors hover:bg-[oklch(var(--primary-hover))]"
         onClick={() => onRespond({ id: descriptor.id, kind: "freetext", text })}
       >
         Send