Phase 6: racket zombies (rally mini-boss)

Survive a horde and a racket zombie takes up residence on the far court
(variant 'r', one per horde survived) — the tennis rally skill lives on
inside zombie mode. It reuses the turned-CPU z_c sprite (already holds a
racket) and a slimmed copy of the tennis AI: holds station deep, chases a
ball laterally at TUNE.racketSpeed (2.8), and returns your SOFT shots
(pow < zSplatQ) as live lastHit:'O' balls with quality capped at
racketQMax (0.55) and racketFlub (0.2) whiffs. trySwing gained an
optional quality-cap arg (defaulted, so tennis is untouched).

It's a mini-boss with TUNE.racketHp (3): only splat-quality balls hurt it
(-1 hp, staggers the ball; the killing blow runs the full splatter). Soft
balls pass through for it to rally; melee and pellets don't touch it. Its
return that gets past your baseline is a point for THEM; you can rally it
back with the existing player hit. A red HP bar floats over its head.

Verified via window.T: endHorde spawns exactly one (hp 3, z 3.5); three
splat hits kill it (2→1→dead); a pow-0.3 ball is returned toward you; an
'O' ball past your baseline scores for THEM; melee spares the boss but
cleaves the shambler beside it; tennis still 12/11/12 and a normal
shambler is still one-shot; renders with its HP bar; no console errors.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

render.js

@@ -123,8 +123,15 @@ function drawBoy(b) {
   ctx.restore();
 }
 function drawZombie(zb) {
-  const frame = Math.floor(zb.walkT * 2.6) % 2 + 1;
-  drawStatic('z_' + zb.variant + frame, zb.x, zb.z, 1.8, Math.floor(zb.walkT * 5.2) % 2);
+  const rk = zb.variant === 'r';
+  const v = rk ? 'c' : zb.variant; // the racket boss reuses the turned-CPU sprite (already holds a racket)
+  const frame = rk && zb.pose === 'swing' ? 2 : Math.floor(zb.walkT * 2.6) % 2 + 1;
+  drawStatic('z_' + v + frame, zb.x, zb.z, rk ? 1.85 : 1.8, Math.floor(zb.walkT * 5.2) % 2);
+  if (rk) { // HP bar floating above the mini-boss
+    const p = proj(zb.x, 2.05, zb.z), w = Math.max(10, p.s * 0.5), x = p.x - w / 2;
+    ctx.fillStyle = '#300'; ctx.fillRect(x, p.y, w, 3);
+    ctx.fillStyle = '#e03030'; ctx.fillRect(x, p.y, w * Math.max(0, zb.hp) / TUNE.racketHp, 3);
+  }
 }
 function drawRing(x, z, color) {
   const p = proj(x, 0, z);