Phase 12: the weapon ladder — every tin opens something nastier

Deliveries cycle BOMB -> TRIPLE -> FIRE -> GUN (G.deliveries indexes the
ladder); one tin at a time, a fresh delivery replaces unspent stock. All
weapons stay one-thumb: the serve auto-consumes, zero new inputs.

- Triple serve (x3): one real serve fans two ballistic clones +-6deg (extras[]
  in zombies.js — NOT the reverted rapid-fire: each fan costs a proper serve).
  Side balls respect variant rules (wound brutes, clank off chairs, pass the boss)
- Flame ball (x3): kills on ANY contact regardless of pow, chair ignored,
  full pierce (splatter pace tax undone), ember trail, white-hot render
- Machine gun (8s): horde auto-fire as a pickup — no serving, drag steers,
  no assist, spawner keeps running, ammo bar drains on the HUD, then the
  serve loop resumes
- HUD pips per type (black/yellow/orange) at the bomb slot; flash names the
  tin ('NEW BALLS: FIRE')

Verified: ladder cycles across 5 deliveries; triple spawns 2 extras and the
fan kills flanked targets; pow-0.1 flame ball clears shambler+shield+brute in
one pass with TRIPLE KILL chaining; GUN tin arms at changeover, blocks taps,
streams pellets (kill in 5 frames), expires back to pretoss; tennis 11/12;
no weapon-flag leaks into tennis; no console errors.

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

main.js

@@ -8,7 +8,7 @@ import { P, O, ball, score, G, setupPoint } from './state.js';
 import { update, keyPressed, solveShot, inServeBox, inCourt, forceZombies, splatPoint } from './gameplay.js';
 import { fitViewport, render, proj } from './render.js';
 import { voice } from './audio.js';
-import { zombies, spawnZombie, piles, gore, parts, pellets, explode } from './zombies.js';
+import { zombies, spawnZombie, piles, gore, parts, pellets, extras, explode } from './zombies.js';
 import { cv } from './dom.js';
 import './input.js';
 
@@ -54,6 +54,6 @@ cv.addEventListener('pointerdown', e => {
 requestAnimationFrame(frame);
 
 // exposed for in-browser sanity checks and simulated playtests
-window.T = { TUNE, ball, P, O, score, G, zombies, spawnZombie, piles, gore, parts, pellets, explode, splatPoint, solveShot, inServeBox, inCourt, proj, setupPoint, forceZombies,
+window.T = { TUNE, ball, P, O, score, G, zombies, spawnZombie, piles, gore, parts, pellets, extras, explode, splatPoint, solveShot, inServeBox, inCourt, proj, setupPoint, forceZombies,
   step: dt => update(dt), render, press: keyPressed,
   get phase() { return G.phase; }, set phase(v) { G.phase = v; } };