Catchability contract: every ball reachable via auto-run, timing is the skill

- intercept() now picks a point the runner can actually reach in time
  (travel-time feasibility), falling back to the deepest hittable point
- tapping no longer slows the auto-run: anticipating a shot doesn't lose it
- assist legs slightly superhuman (1.15x) so positioning is guaranteed
- ball boy run frames regenerated with contrasting stride/gather poses
  (previous pair was near-identical, which read as no animation)

Verified: 10/10 CPU shots end inside the honest 1.3m contact radius with
zero manual movement.

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

game.js

@@ -18,7 +18,7 @@ const TUNE = {
   aimError: 2.4,           // m of scatter at quality 0
   perfectMs: 45,           // |offset from window center| for PERFECT
   aiQualityMin: 0.55, aiQualityMax: 0.95, aiFlub: 0.05,
-  autoAssist: matchMedia('(pointer: coarse)').matches ? 1.0 : 0, // auto-run toward the ball (mobile)
+  autoAssist: matchMedia('(pointer: coarse)').matches ? 1.15 : 0, // auto-run speed factor (mobile); slightly superhuman legs
 };
 
 const COURT = { L: 23.77, W: 8.23, dblW: 10.97, netZ: 11.885, netH: 0.914, netW: 10.06, serviceD: 6.4 };
@@ -367,24 +367,29 @@ function onBounce() {
 let phaseWasServe = false;
 
 // ---------------------------------------------------------------- update ----
-// Where should a player run to? Simulate the ball forward and take the first point
-// in their half where the ball is at comfortable hitting height.
+// Where should a player run to? Simulate the ball forward and take the first point in
+// their half at hitting height that they can actually REACH IN TIME; otherwise chase the
+// deepest hittable point. This is the "every ball is catchable, timing is the skill" contract.
 function intercept(side) {
+  const ch = side === 'O' ? O : P;
+  const spd = side === 'O' ? TUNE.aiSpeed : TUNE.playerSpeed * TUNE.autoAssist;
   let { x, y, z, vx, vy, vz } = ball;
   const g = TUNE.gravity, dt = 0.01;
   const inZone = side === 'O' ? zz => zz <= 9.5 : zz => zz >= COURT.L - 9.5;
   const home = side === 'O' ? { x: 0, z: 2.5 } : { x: 0, z: 22.8 };
-  let fallback = null;
-  for (let i = 0; i < 240; i++) {
+  let fallback = null, deepest = null;
+  for (let i = 0; i < 300; i++) {
     vy -= g * dt; x += vx * dt; y += vy * dt; z += vz * dt;
     if (y <= 0 && vy < 0) { y = 0; vy = -vy * TUNE.bounceY; vx *= TUNE.bounceXZ; vz *= TUNE.bounceXZ; }
-    if (i > 5 && inZone(z) && y < 1.6) {
+    if (i > 5 && inZone(z) && y < 1.6 && y > 0.3) {
       const pt = { x, z: side === 'O' ? Math.max(0.8, z) : Math.min(24.5, z) };
-      if (y > 0.7) return pt;                                    // waist-high contact preferred
-      if (y > 0.3 && !fallback) fallback = pt;
+      const reachable = Math.hypot(pt.x - ch.x, pt.z - ch.z) / spd <= i * dt;
+      if (y > 0.7 && reachable) return pt;          // waist-high AND arrivable in time
+      if (reachable && !fallback) fallback = pt;    // low but arrivable
+      deepest = pt;                                 // last resort: run at the deepest hittable point
     }
   }
-  return fallback || home;
+  return fallback || deepest || home;
 }
 
 function trySwing(ch, isAI) {
@@ -448,7 +453,8 @@ function update(dt) {
       let assist = 0;
       if (!mx && !mz && TUNE.autoAssist > 0 && ball.active) {
         const chasing = ball.lastHit === 'O';
-        const rate = TUNE.playerSpeed * TUNE.autoAssist * slow * dt * (chasing ? 1 : 0.55);
+        // no `slow` here: tapping must not freeze your legs, or anticipating a shot loses it
+        const rate = TUNE.playerSpeed * TUNE.autoAssist * dt * (chasing ? 1 : 0.55);
         const tgt = chasing ? intercept('P') : { x: 0, z: 22.8 }; // run to the ball, then recover home
         const dx = tgt.x - P.x, dz = tgt.z - P.z, d = Math.hypot(dx, dz);
         if (d > 0.35) { // deadzone: stand ready near the spot instead of dithering over it