feat(handtracking): restyle svg visualizer and add silhouette fallback

src/components/ui/GameUI.tsx

@@ -1,6 +1,7 @@
 import { Crosshair } from "@/components/ui/Crosshair";
 import { DebugOverlayLayout } from "@/components/ui/debug/DebugOverlayLayout";
 import { GameSettingsMenu } from "@/components/ui/GameSettingsMenu";
+import { HandTrackingFallback } from "@/components/ui/HandTrackingFallback";
 import { HandTrackingVisualizer } from "@/components/ui/HandTrackingVisualizer";
 import { InteractPrompt } from "@/components/ui/InteractPrompt";
 import { RepairMovementLockIndicator } from "@/components/ui/RepairMovementLockIndicator";
@@ -15,6 +16,7 @@ export function GameUI(): React.JSX.Element {
       <RepairMovementLockIndicator />
       <InteractPrompt />
       <HandTrackingVisualizer />
+      <HandTrackingFallback />
       <Subtitles />
       <TalkieDialogueOverlay />
       <GameSettingsMenu />

src/components/ui/HandTrackingFallback.tsx

@@ -0,0 +1,82 @@
+import { useHandTrackingSnapshot } from "@/hooks/handTracking/useHandTrackingSnapshot";
+import {
+  useHandTrackingGloveStatus,
+  type HandTrackingGloveHandedness,
+} from "@/hooks/handTracking/useHandTrackingGloveStatus";
+
+// Simple schematic silhouettes used as a last-resort fallback when the
+// rigged glove model has failed to load. Both icons share the same
+// 48x48 viewBox and the same stroke/fill rules from the .css.
+
+const OpenHandShape = (): React.JSX.Element => (
+  <>
+    <ellipse cx="9" cy="30" rx="3" ry="6" transform="rotate(-25 9 30)" />
+    <rect x="14" y="8" width="4" height="22" rx="2" />
+    <rect x="20" y="4" width="4" height="26" rx="2" />
+    <rect x="26" y="6" width="4" height="24" rx="2" />
+    <rect x="32" y="10" width="4" height="20" rx="2" />
+    <rect x="10" y="26" width="28" height="18" rx="6" />
+  </>
+);
+
+const FistShape = (): React.JSX.Element => (
+  <>
+    <ellipse cx="8" cy="26" rx="3" ry="5" />
+    <rect x="10" y="14" width="28" height="30" rx="10" />
+    <circle cx="15" cy="14" r="3" />
+    <circle cx="21" cy="13" r="3" />
+    <circle cx="27" cy="13" r="3" />
+    <circle cx="33" cy="14" r="3" />
+  </>
+);
+
+function getHandedness(raw: string): HandTrackingGloveHandedness | null {
+  const lower = raw.toLowerCase();
+  if (lower === "left" || lower === "right") return lower;
+  return null;
+}
+
+export function HandTrackingFallback(): React.JSX.Element | null {
+  const { hands } = useHandTrackingSnapshot();
+  const gloveStatus = useHandTrackingGloveStatus((state) => state.gloves);
+
+  const visibleHands = hands.flatMap((hand, index) => {
+    const handedness = getHandedness(hand.handedness);
+    if (!handedness) return [];
+    if (gloveStatus[handedness] !== "error") return [];
+
+    const wrist = hand.landmarks[0];
+    if (!wrist) return [];
+
+    return [{ hand, handedness, wrist, index }];
+  });
+
+  if (visibleHands.length === 0) return null;
+
+  return (
+    <div className="hand-tracking-fallback" aria-hidden="true">
+      {visibleHands.map(({ hand, handedness, wrist, index }) => {
+        // MediaPipe coords are mirrored (selfie cam), keep the same
+        // mapping the SVG visualizer uses.
+        const leftPercent = (1 - wrist.x) * 100;
+        const topPercent = wrist.y * 100;
+        const flipX = handedness === "right" ? -1 : 1;
+
+        return (
+          <svg
+            key={`${handedness}-${index}`}
+            className="hand-tracking-fallback__icon"
+            viewBox="0 0 48 48"
+            style={{
+              left: `${leftPercent}%`,
+              top: `${topPercent}%`,
+              transform: `translate(-50%, -50%) scaleX(${flipX})`,
+            }}
+          >
+            {hand.isFist ? <FistShape /> : <OpenHandShape />}
+          </svg>
+        );
+      })}
+    </div>
+  );
+}

src/components/ui/HandTrackingVisualizer.tsx

@@ -26,6 +26,12 @@ const HAND_CONNECTIONS: Array<[number, number]> = [
   [0, 17],
 ];
 
+const LANDMARK_FILL = "#67e8f9"; // cyan-300, opaque interior
+const LANDMARK_STROKE = "#0c4a6e"; // sky-900, dark blue outline
+const LANDMARK_STROKE_FIST = "#1e3a8a"; // blue-900, thicker accent when fist
+const CONNECTION_STROKE = "#ffffff"; // white bones
+const INDEX_TIP_LANDMARK = 8;
+
 export function HandTrackingVisualizer(): React.JSX.Element | null {
   const { hands, status } = useHandTrackingSnapshot();
   const showHandTrackingSvg = useDebugStore((debug) =>
@@ -50,7 +56,9 @@ export function HandTrackingVisualizer(): React.JSX.Element | null {
         const landmarks = hand.landmarks;
         if (landmarks.length === 0) return null;
 
-        const color = hand.isFist ? "#facc15" : "#38bdf8";
+        const landmarkStroke = hand.isFist
+          ? LANDMARK_STROKE_FIST
+          : LANDMARK_STROKE;
 
         return (
           <g key={`${hand.handedness}-${handIndex}`}>
@@ -66,8 +74,8 @@ export function HandTrackingVisualizer(): React.JSX.Element | null {
                   y1={`${fromPoint.y * 100}%`}
                   x2={`${(1 - toPoint.x) * 100}%`}
                   y2={`${toPoint.y * 100}%`}
-                  stroke={color}
-                  strokeWidth="2"
+                  stroke={CONNECTION_STROKE}
+                  strokeWidth="2.5"
                   strokeLinecap="round"
                 />
               );
@@ -78,8 +86,10 @@ export function HandTrackingVisualizer(): React.JSX.Element | null {
                 key={landmarkIndex}
                 cx={`${(1 - landmark.x) * 100}%`}
                 cy={`${landmark.y * 100}%`}
-                r={landmarkIndex === 8 ? 5 : 3}
-                fill={landmarkIndex === 8 ? "#ffffff" : color}
+                r={landmarkIndex === INDEX_TIP_LANDMARK ? 6 : 4}
+                fill={LANDMARK_FILL}
+                stroke={landmarkStroke}
+                strokeWidth={hand.isFist ? 2.5 : 2}
               />
             ))}
           </g>