Two-stage serve aim: hold + drag shows the reticle, release fires

Flick-to-aim was aim-by-faith — you learned where you aimed after the ball
was gone. Now, at a serveable pretoss, touching and dragging shows a LIVE
reticle (same mapping: direction + length = landing point); release serves
there. The magnet is finally visible: within zSnap the ring turns red and
rides the locked zombie (plus a marker over its head) — you see the lock
BEFORE you commit the tin.

- Context locked at touchstart: a movement drag started mid-rally never
  morphs into a serve when the ball dies (sub-300ms releases still count
  as the rapid flick re-serve — the Phase 1 cadence survives)
- Drag back home = cancel: no serve, the tin stays in stock
- Aimed (drag) serves commit specials at fixed 0.62 quality; the tap-toss
  ritual keeps the PERFECT-timing power ceiling and the stock — placement
  vs power is now a real choice
- Rally / horde / machine gun untouched: drag steers, flick swings
- Serve prompt: 'TAP TO SERVE - HOLD + DRAG TO AIM' / 'AIMED SERVES FIRE
  THE BOMB - TAP KEEPS IT'

Verified with synthetic touch sequences: drag arms the reticle without
serving and it tracks the thumb; release serves at the marker with the bomb
committed; cancel keeps the tin; rally-started drags never morph; locked
reticle renders red on the zombie (screenshot); tennis 12/12; no console
errors.

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

input.js

@@ -4,7 +4,8 @@
 
 import { cv } from './dom.js';
 import { audio } from './audio.js';
-import { keyPressed } from './gameplay.js';
+import { G, score } from './state.js';
+import { keyPressed, dragServe } from './gameplay.js';
 import { togglePanel } from './panel.js';
 
 const keys = {};
@@ -36,10 +37,17 @@ export function takeFlickAim(maxAgeMs = 450) {
   return null;
 }
 
+// the two-stage serve: a drag that STARTS at a serveable pretoss aims a visible reticle
+// (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;
+
 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 };
+    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
     else keyPressed('Space');
   }
 }, { passive: false });
@@ -49,8 +57,12 @@ cv.addEventListener('touchmove', e => {
   if (!stick) return;
   for (const t of e.changedTouches) {
     if (t.identifier !== stick.id) continue;
-    const dx = t.clientX - stick.x0, dy = t.clientY - stick.y0;
-    if (Math.hypot(dx, dy) > DEAD) stick.moved = true;
+    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;
+      continue;
+    }
     touchAxis.x = Math.abs(dx) > DEAD ? Math.sign(dx) : 0;
     touchAxis.z = Math.abs(dy) > DEAD ? Math.sign(dy) : 0;
   }
@@ -62,7 +74,12 @@ 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.moved && dt < 250) keyPressed('Space');                     // tap
+    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
+    }
+    else if (!stick.moved && dt < 250) keyPressed('Space');                // tap
     else if (dt < 300 && dist > 28) {                                      // flick = aimed swing
       flickAim = { ax: Math.abs(dx) > dist * 0.38 ? Math.sign(dx) : 0,
                    az: Math.abs(dy) > dist * 0.38 ? Math.sign(dy) : 0,