Pin the canvas height to what is actually visible, and three fixes

Viewport, again — the homescreen app was the case that broke it. Watching for a
signal cannot work there: launched standalone, iOS resolves the CSS viewport once
against a provisional box and never re-resolves it, so no resize, no layout
change, nothing for a ResizeObserver to observe. Only a rotation forced the issue.
So the CSS box is now a proposal: visualViewport says what is really visible and
the height gets pinned in px to match, re-read on every fit — plus a short settle
salvo after launch, since that launch announces nothing.

- The countdown skipped the transition, where overT is parked at 9999 to hold the
  point flow. It read as RESUMING IN 9999 after the first game you ever win.
- Countdown moved off the HUD line into the open, at a readable size.
- A returned shot is a glancing blow now, not a mirror. Reversing the incoming
  line sent every parry straight back up it — into the thrower — so a boss handed
  you a free wound per volley. Contact across the racket face sets the angle:
  dead centre still goes back at him, which is a placement you earn.

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

zombies.js

@@ -608,9 +608,16 @@ export function updateZombies(dt) {
     if (!done && P.swingT >= 0 && P.swingT <= TUNE.parryWindow
         && dP < TUNE.parryReach && s.y < CONTACT.maxY) {
       // the parry: it becomes an `extras` clone — that array is already ballistic and already kills
-      // zombies, so "returned shot is a live weapon" costs nothing to build
+      // zombies, so "returned shot is a live weapon" costs nothing to build.
+      // It is a GLANCING blow, not a mirror. Reversing the incoming line sent every return straight
+      // back up the line it arrived on — which is where the thrower is standing — so a boss was a
+      // free wound per throw. Where you meet the ball across the racket face now sets the angle:
+      // hitting it back INTO him is a shot you have to place your feet for.
+      const off = Math.max(-1, Math.min(1, (s.x - P.x) / TUNE.parryReach)); // -1..1 across the face
+      const ang = (off * TUNE.parryDeflect + (Math.random() * 2 - 1) * TUNE.parryJitter) * Math.PI / 180;
+      const sp = Math.hypot(s.vx, s.vz) * 1.15;
       extras.push({ x: s.x, y: s.y, z: s.z, g: TUNE.gravity, pow: TUNE.parryPow, t: 2.5,
-        vx: s.vx * 0.3, vy: 4.2, vz: -Math.abs(s.vz) * 1.15 });
+        vx: Math.sin(ang) * sp, vy: 4.2, vz: -Math.cos(ang) * sp });
       pock(0.85, 1300); G.flash = { text: 'RETURNED', t: 0.6 }; cheer(0.8, 0.3);
       done = true;
     }