Fix the freeze; duel intro card + tennis lights; hold-to-aim; instant gun steering

THE FREEZE (root cause found): the game-winning kill fires INSIDE the zombie
update loop — killZombie -> splatPoint -> gameOver -> sweepCourt guts the
zombies array mid-iteration, the loop reads zombies[i] === undefined, throws,
and the un-rescheduled RAF chain dies: a permanent hard freeze. Crowded courts
(later games, brutes) make the mid-loop game-winner likelier — hence 'freezes
around game 3 when the fat zombies arrive'. Fixed at the root (null guards in
every loop whose body can cascade into a sweep: zombie walk loop, meleeSwipe,
explode, pellet + extras inner loops) AND made frame() reschedule RAF FIRST so
no single bad frame can ever kill the loop again.

Aim awareness: the reticle now appears the moment the thumb lands (mag 0 =
auto-target the most advanced zombie, red lock immediately). A pure HOLD
(>250ms, no drag) releases into the auto-target serve; dragging aims as
before; the serve prompt switches to 'RELEASE TO SERVE / RELEASE FIRES THE
BOMB - DRAG BACK TO CANCEL' while aiming.

Duel presentation: the interlude now opens with a 2.4s intro beat — serving
blocked, centered card (SUDDEN DEATH / ONE POINT - THE LINES ARE LIVE / WIN
IT FOR THE NEXT TIN), and the palette lerps back to the TENNIS colors for
the duration of the duel (duelLerp, 0.8s each way) — order visibly restored,
then the rot returns.

Machine-gun steering: absolute now — the finger x IS the player x, zero lag
(was sign-quantized velocity). Clamped to what the camera can see
((W/2-14)/proj-scale — portrait's world bounds are wider than its viewport),
keyboard steering clamped the same during auto-fire.

Verified: the exact pre-fix crash scenario (game-winning kill mid-loop,
9 zombies + brute) survives and sweeps clean; intro blocks taps then the
duel plays; hold-release fired at the auto-lock and won a tin end-to-end;
screenshot shows tennis-green court + centered card + GAME 2; MG jumps
P.x to the finger in one frame, clamped; tennis 12/12; no console errors.

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

input.js

@@ -41,13 +41,21 @@ export function takeFlickAim(maxAgeMs = 450) {
 // (G.aim, drawn by render); release fires the serve there, dragging back home cancels.
 const canAimServe = () =>
   G.mode === 'splatter' && G.phase === 'pretoss' && score.server === 'P'
-  && !G.horde && !(G.mgT > 0) && !G.changeover;
+  && !G.horde && !(G.mgT > 0) && !G.changeover && !(G.interlude && G.interlude.introT > 0);
+
+let steerPX = null; // live absolute finger x (-1..1 across the canvas) — machine-gun steering reads it
+export const touchPX = () => steerPX;
 
 cv.addEventListener('touchstart', e => {
   e.preventDefault(); audio();
   for (const t of e.changedTouches) {
-    if (!stick) stick = { id: t.identifier, x0: t.clientX, y0: t.clientY, t0: performance.now(),
-                          moved: false, aimable: canAimServe() }; // context locked at touch start — a movement drag never morphs into a serve
+    if (!stick) {
+      stick = { id: t.identifier, x0: t.clientX, y0: t.clientY, t0: performance.now(),
+                moved: false, aimable: canAimServe() }; // context locked at touch start — a movement drag never morphs into a serve
+      // the reticle appears the moment the thumb lands: mag 0 = auto-target the most advanced
+      if (stick.aimable) G.aim = { fx: 0, fy: 0, mag: 0 };
+      else { const r = cv.getBoundingClientRect(); steerPX = (t.clientX - r.left) / r.width * 2 - 1; }
+    }
     else keyPressed('Space');
   }
 }, { passive: false });
@@ -59,10 +67,12 @@ cv.addEventListener('touchmove', e => {
     if (t.identifier !== stick.id) continue;
     const dx = t.clientX - stick.x0, dy = t.clientY - stick.y0, dist = Math.hypot(dx, dy);
     if (dist > DEAD) stick.moved = true;
-    if (stick.aimable) { // aiming, not steering: the reticle tracks the thumb
-      G.aim = dist > DEAD ? { fx: dx / dist, fy: dy / dist, mag: dist } : null;
+    if (stick.aimable) { // aiming, not steering: the reticle tracks the thumb (home = auto-target)
+      G.aim = dist > DEAD ? { fx: dx / dist, fy: dy / dist, mag: dist } : { fx: 0, fy: 0, mag: 0 };
       continue;
     }
+    const r = cv.getBoundingClientRect();
+    steerPX = (t.clientX - r.left) / r.width * 2 - 1;
     touchAxis.x = Math.abs(dx) > DEAD ? Math.sign(dx) : 0;
     touchAxis.z = Math.abs(dy) > DEAD ? Math.sign(dy) : 0;
   }
@@ -74,10 +84,11 @@ const endTouch = e => {
     if (!stick || t.identifier !== stick.id) continue;
     const dt = performance.now() - stick.t0;
     const dx = t.clientX - stick.x0, dy = t.clientY - stick.y0, dist = Math.hypot(dx, dy);
-    if (stick.aimable && stick.moved) {                                    // two-stage release
-      const aim = G.aim; G.aim = null;
-      if (aim && dist > DEAD * 1.5) dragServe(aim);                        // on target — serve
-      // else: dragged back home — cancel, the tin stays in stock
+    const aim = G.aim; G.aim = null; steerPX = null;
+    if (stick.aimable && (stick.moved || dt >= 250)) {                     // two-stage release
+      // a pure HOLD (never moved) fires at the auto-target; a drag fires at the reticle;
+      // a drag walked back home cancels — the tin stays in stock
+      if (aim && (!stick.moved || dist > DEAD * 1.5)) dragServe(aim);
     }
     else if (!stick.moved && dt < 250) keyPressed('Space');                // tap
     else if (dt < 300 && dist > 28) {                                      // flick = aimed swing