The rounds stay, the seams go: one continuous stream

Oliver: "daniel announcing is maximum annoying" / "don't let the rush in
position just let them coming from the back in steady speed.. try to space
them not too close" / "when one combination is done just let the new one in..
in a continuous stream that increases in speed and difficulty" / "the rounds
can stay, they should be continuous".

The round survives as the unit. Every seam around it is deleted: no walk-on
to a mark, no announcement beat, no between-rounds pause, no deal. Bodies
walk in from the far baseline forever and a round is drawn from whoever is on
court — finish one and the next is drawn in the same frame, off the same
rolling population. The bodies you were ignoring a second ago are the ones
being called now.

- Daniel is gone from this mode. Each colour has a pitch; a round announces
  itself as a four-note figure in half a second (blip()). drillTones 0 mutes
  it. The recordings stay in assets.
- PLACEMENTS is deleted with the marks — nothing rushes anywhere and nothing
  stops, so there are no shapes to place.
- A DRILL BODY HOLDS ITS LANE. updateZombies homes bodies onto the player's x
  past the net, so they arrived spread and bunched into a knot right in front
  of you; spawn spacing cannot survive that. Their lane is the puzzle here.
- One ramp on TIME SURVIVED drives speed, spawn gap and round length. Speed
  is stamped per body at spawn, so the ramp reads as newcomers outpacing the
  ones already walking, not the court accelerating under you.
- The empty-court watchdog is gone and nothing replaced it: with a stream
  there is no state to be stuck in. One line covers every case.

27 tests, rewritten around the stream.

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

src/beats.js

@@ -12,7 +12,7 @@ import { G, P, ball, score, setupPoint, sendBoy } from './state.js';
 import { voice, zombieDuck, aww } from './audio.js';
 import { zombies, pellets, extras, shots, spawnRacketZombie, spawnChapterBoss, spawnZombie } from './zombies.js';
 import { cheer, aside, endBurst, deliverTin, showModal, logSwing } from './gameplay.js';
-import { newDrillRound } from './drill.js';
+import { startDrillStream } from './drill.js';
 
 // the court is mopped up (or was already clear): play advances to whatever the won game earned —
 // a changeover breather, a plain even-game beat, or (on a set) the centered SET card then a horde.
@@ -136,7 +136,7 @@ export function endBossFight() {
 // clock and rules live in drill.js; only the transition is here, where the rule can be enforced.
 export function startDrill() {
   if (G.drill || G.interlude || G.horde || G.bossFight) return false;
-  G.drill = { seq: [], step: 0, faults: 0, callT: 0, beat: 0, rush: 0, won: 0, lost: 0, msg: null };
+  G.drill = { seq: [], step: 0, faults: 0, t: 0, spawnT: 0, rounds: 0, lost: 0, msg: null };
   G.changeover = false; G.clearing = false; G.afterClear = null;
   // ...and DISARM the ordinary schedule. Taking the court is not enough on its own: a pending
   // horde, an owed chapter or a due duel is a latch that keeps trying to fire behind the drill,
@@ -147,7 +147,7 @@ export function startDrill() {
   G.weapon = 0;                     // plain balls: the mode is about order, not about the rack
   ball.active = false; setupPoint();
   voice('quiet_please', 0.1);
-  newDrillRound();
+  startDrillStream();
   return true;
 }