feat(RealityOverridePage): implement star field animation beneath Three.js vortex

src/app/components/RealityOverridePage.tsx

@@ -5,7 +5,23 @@ import { EffectComposer } from 'three/examples/jsm/postprocessing/EffectComposer
 import { RenderPass }     from 'three/examples/jsm/postprocessing/RenderPass.js';
 import { UnrealBloomPass } from 'three/examples/jsm/postprocessing/UnrealBloomPass.js';
 
-interface Msg { text: string; id: number; }
+interface Msg  { text: string; id: number; }
+interface Star { x: number; y: number; sz: number; ph: number; spd: number; col: [number, number, number]; }
+
+const STAR_PALETTE: [number, number, number][] = [
+  [255, 255, 255], [255, 240, 210], [210, 220, 255], [255, 210, 210], [200, 255, 230],
+];
+
+function mkStar(W: number, H: number): Star {
+  return {
+    x: Math.random() * W | 0,
+    y: Math.random() * H | 0,
+    sz: Math.random() < 0.8 ? 1 : Math.random() < 0.6 ? 2 : 3,
+    ph: Math.random() * Math.PI * 2,
+    spd: Math.random() * 0.04 + 0.005,
+    col: STAR_PALETTE[Math.random() * STAR_PALETTE.length | 0],
+  };
+}
 
 // ── Shaders (verbatim from public/vortex/script.js) ──────────────────────────
 
@@ -79,6 +95,8 @@ const FRAG_TRAIL = `
 
 export default function RealityOverridePage({ onBack }: { onBack: () => void }) {
   const containerRef = useRef<HTMLDivElement>(null);
+  const starCanvasRef = useRef<HTMLCanvasElement>(null);
+  const starsRef      = useRef<Star[]>([]);
   const wsRef        = useRef<WebSocket | null>(null);
   const msgIdRef     = useRef(0);
   const fadeTimer    = useRef<ReturnType<typeof setTimeout> | undefined>(undefined);
@@ -231,6 +249,43 @@ export default function RealityOverridePage({ onBack }: { onBack: () => void })
     };
   }, []);
 
+  // ── Star field (always running, visible under Three.js when vortex is hidden) ─
+  useEffect(() => {
+    const canvas = starCanvasRef.current;
+    if (!canvas) return;
+    let animId = 0;
+    let prevW = 0, prevH = 0;
+
+    const loop = () => {
+      const W = canvas.clientWidth, H = canvas.clientHeight;
+      if (!W || !H) { animId = requestAnimationFrame(loop); return; }
+      if (W !== prevW || H !== prevH) {
+        canvas.width = W; canvas.height = H;
+        prevW = W; prevH = H;
+        starsRef.current = Array.from({ length: 200 }, () => mkStar(W, H));
+      }
+      const ctx = canvas.getContext('2d')!;
+      ctx.fillStyle = '#000010';
+      ctx.fillRect(0, 0, W, H);
+      for (const st of starsRef.current) {
+        st.ph += st.spd;
+        const br = Math.sin(st.ph) * 0.4 + 0.6;
+        const [r, g, b] = st.col;
+        ctx.fillStyle = `rgba(${r},${g},${b},${br})`;
+        ctx.fillRect(st.x, st.y, st.sz, st.sz);
+        if (st.sz >= 3 && br > 0.85) {
+          ctx.fillStyle = `rgba(${r},${g},${b},${br * 0.35})`;
+          ctx.fillRect(st.x - 2, st.y + 1, st.sz + 4, 1);
+          ctx.fillRect(st.x + 1, st.y - 2, 1, st.sz + 4);
+        }
+      }
+      animId = requestAnimationFrame(loop);
+    };
+
+    animId = requestAnimationFrame(loop);
+    return () => cancelAnimationFrame(animId);
+  }, []);
+
   // ── WebSocket ───────────────────────────────────────────────────────────────
   useEffect(() => {
     let cancelled = false;
@@ -266,7 +321,10 @@ export default function RealityOverridePage({ onBack }: { onBack: () => void })
       onTouchEnd={handleTouchEnd}
     >
 
-      {/* Three.js canvas mount */}
+      {/* Star field — always visible beneath the vortex */}
+      <canvas ref={starCanvasRef} className="absolute inset-0 w-full h-full" style={{ imageRendering: 'pixelated' }} />
+
+      {/* Three.js vortex — fades out on double-click/tap */}
       <div ref={containerRef} className={`absolute inset-0 transition-opacity duration-500 ${bgVisible ? 'opacity-100' : 'opacity-0'}`} />
 
       {/* CSS keyframe for command flash */}