Split the monolith into ES modules; hoist scattered magic numbers

game.js (830 lines) -> 9 modules, native ES modules so still zero build step:
  dom      canvas handles (imports nothing; keeps cycles harmless)
  config   TUNE (live-tunable) + structural constants
  state    all mutable game state (G) + setupPoint/sendBoy
  audio    sfx synthesis, recorded umpire voice, reverb, speech fallback
  input    keyboard + touch, exports axes and takeFlickAim()
  gameplay ballistics, swings, serve, rules, AI, update loop
  render   camera, viewport, sprites, crowd, all drawing
  panel    T tuning UI
  main     boot, loop, intro, window.T test hooks

Deduped into named constants: bounce tempo (was in 3 places), contact
height band, intercept zone depth, home positions, player bounds, toss
params, shot depths, pose hold time, sprite scale, actor heights. Also
extracted drawShadow/drawBall/expirePose from repeated code.

One intentional import cycle (input <-> gameplay), safe: both sides only
call functions at runtime, never during module evaluation.

Regression-verified in browser sims: point cycle, CPU returns 11/12,
assist contract 8/8, corner-winner gradient intact (0/12 perfect corners
returned, 10/12 center balls returned).

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

config.js

@@ -0,0 +1,57 @@
+// All tuning and constants. TUNE is live-editable in game via the T panel;
+// the exported consts below are structural values that code shares but the panel doesn't show.
+
+export const TUNE = {
+  camZ: 36, camY: 9, camF: 280, horizon: 40,
+  gravity: 9.2,            // slightly floaty vs 9.8 for readability
+  spinFactor: 0.9,         // extra dive on quality shots (fake topspin)
+  bounceY: 0.58, bounceXZ: 0.78,
+  playerSpeed: 5.4, aiSpeed: 4.3,
+  reach: 1.3, aiReach: 1.6, // tight contact radius: the assist positions you, the tap must be honest
+  swingWindup: 0.06,       // s before contact window opens
+  swingWindow: 0.16,       // s contact window length
+  baseShotSpeed: 16, qualityShotSpeed: 12,  // horizontal m/s = base + q*quality; perfect timing = real pace
+  serveSpeed: 21, serveQualitySpeed: 7,
+  aimError: 2.4,           // m of scatter at quality 0
+  perfectMs: 45,           // |offset from window center| for PERFECT
+  aiQualityMin: 0.45, aiQualityMax: 0.85, aiFlub: 0.09,
+  aiReaction: 0.45,        // s before the CPU reads your shot — well-aimed corners are winners
+  autoAssist: matchMedia('(pointer: coarse)').matches ? 1.15 : 0, // auto-run speed factor (mobile)
+};
+
+export const COURT = { L: 23.77, W: 8.23, dblW: 10.97, netZ: 11.885, netH: 0.914, netW: 10.06 };
+COURT.svcFar = COURT.netZ - 6.4;   // far service line
+COURT.svcNear = COURT.netZ + 6.4;  // near service line
+
+// world sizes (meters)
+export const PLAYER_H = 1.88;
+export const BOY_H = 1.2;
+export const UMP_H = 2.7;
+
+// contact rules: outside this height band the ball can't be hit (below = it's past you)
+export const CONTACT = { minY: 0.24, maxY: 2.3 };
+
+// how deep from the far/near baseline a player's interception zone extends
+export const ZONE_DEPTH = 9.5;
+
+// recovery positions between shots
+export const HOME = { P: { x: 0, z: 22.8 }, O: { x: 0, z: 2.5 } };
+
+// where the near player is allowed to move
+export const P_BOUNDS = { x: 6.5, zMin: COURT.netZ + 1.2, zMax: 26 };
+
+// serve toss: release height and upward speed (apex derives from these + gravity)
+export const TOSS = { y0: 1.8, vy: 4.6 };
+
+// shot target depth from the receiving baseline, by aim (up = deep, none = mid, down = short)
+export const SHOT_DEPTH = { deep: 3.0, mid: 5.4, short: 8.6 };
+
+// how long swing/serve poses hold before returning to idle (s)
+export const POSE_TIME = 0.38;
+
+// the server's idle ball bounce: sideways offset to the free hand, apex height, tempo.
+// tempo drives the ball, the hand sprite AND the pock sound — one value, always in sync.
+export const BOUNCE_IDLE = { dx: 0.5, apex: 0.55, tempo: 3.6 };
+
+// generated sprite sheets: the idle pose is this many pixels tall; all scales derive from it
+export const SPRITE_H = 112;