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/viewers/SqlViewer.tsx

@@ -18,9 +18,9 @@ const STATUS_LABELS: Record<string, string> = {
 };
 
 const STATUS_CLASSES: Record<string, string> = {
-  passed: "bg-green-100 text-green-800",
-  failed: "bg-red-100 text-red-800",
-  untested: "bg-gray-100 text-gray-600",
+  passed: "bg-[oklch(var(--success)/0.15)] text-[oklch(0.45_0.12_165)] ring-1 ring-[oklch(var(--success)/0.3)]",
+  failed: "bg-destructive/10 text-destructive ring-1 ring-destructive/25",
+  untested: "bg-muted text-muted-foreground ring-1 ring-border",
 };
 
 function Block({ block }: { block: SqlBlock }) {
@@ -43,7 +43,7 @@ function Block({ block }: { block: SqlBlock }) {
     : "";
 
   return (
-    <div className="sql-block border rounded mb-2">
+    <div className="sql-block rounded-lg border border-border/70 mb-2">
       <button
         className="w-full flex items-center gap-2 px-3 py-2 text-left font-mono text-sm hover:bg-muted/30"
         onClick={() => setOpen((o) => !o)}
@@ -58,7 +58,7 @@ function Block({ block }: { block: SqlBlock }) {
         )}
         {badge && (
           <span
-            className={`ml-auto text-xs px-1.5 py-0.5 rounded ${badgeClass}`}
+            className={`ml-auto text-xs px-1.5 py-0.5 rounded-md ${badgeClass}`}
           >
             {badge}
           </span>
@@ -71,7 +71,7 @@ function Block({ block }: { block: SqlBlock }) {
             // eslint-disable-next-line react/no-danger
             <div dangerouslySetInnerHTML={{ __html: html }} />
           ) : (
-            <pre className="text-sm opacity-50">{block.sql}</pre>
+            <pre className="font-mono text-sm opacity-50">{block.sql}</pre>
           )}
           {block.comments && Object.keys(block.comments).length > 0 && (
             <dl className="mt-2 text-xs text-muted-foreground grid grid-cols-[auto_1fr] gap-x-2 gap-y-0.5">
@@ -96,7 +96,7 @@ export function SqlViewer({ blocks }: { blocks: SqlBlock[] }) {
     <div className="sql-viewer">
       <div className="flex gap-2 mb-2">
         <button
-          className="text-xs px-2 py-1 border rounded hover:bg-muted/30"
+          className="text-xs px-2 py-1 rounded-md border border-border/70 shadow-xs transition-colors hover:bg-accent"
           onClick={() =>
             setLayout((l) => (l === "vertical" ? "horizontal" : "vertical"))
           }