feedback7: the battle sim uses engine-independent math — Chrome, Firefox, Safari and the server agree bit for bit (PR #373 by @Cloudnyco)

- server/sim/detmath.js: hypot (sqrt of the squares, rescaled outside 2^±500), powi (integer powers in double-double,
  one rounding), sin / cos (fdlibm 5.3) and atan2 (fdlibm / FreeBSD msun) built only from correctly rounded IEEE
  operations; the sim's Math.hypot / sin / cos / atan2 / pow calls go through it (65 files); eslint.config.js forbids
  the approximated Math functions under server/sim and test/sim/detmath.test.js scans for them.
- sin / cos / atan2 are the algorithms V8 runs in Node, so the server's results stay; only hypot differs from V8's.
  Golden: 2 moved — diy-027 (a hypot distance, damage +80) and coop3-ABYSS-5 (a later card pick from round 9, same end).
- Applied unchanged after review (Grok static review: MERGE; the diff read in full: no network, no new dependency).
- Tests: broad node --test 5155 / 5155 with the new file tracked (detmath 7 / 7, package 10 / 10); lint 0 errors,
  typecheck, check:imports.

server/sim/content/kits/ops/chess_char_4_12-glady.js

@@ -6,6 +6,7 @@ import {
   AURA, num, tbb, moduleBb, grid, batFlat, enemyHasTag, targetsInRange, whileDeployed, pulse, alt, instantKind,
   pullToFront, withDefaults,
 } from '../shared/tier4.js';
+import { hypot } from '../../../detmath.js';
 
 const ABYSSAL = new Set(['char_143_ghost', 'char_263_skadi', 'char_474_glady', 'char_4145_ulpia', 'char_1023_ghost2']);
 const isAbyssal = (u) => u?.def?.raw?.groupId === 'abyssal' || ABYSSAL.has(u?.def?.charId ?? u?.def?.raw?.charId);
@@ -28,7 +29,7 @@ export default withDefaults({
     };
     // module HOK-Y: "向自身拖拽较远的敌人时力度提升一个等级"
     const farR = num(mb['skill@range_radius'], num(mb['attack@range_radius'], 0)), farF = num(mb['skill@delta_force'], num(mb['attack@delta_force'], 0));
-    const selfForce = (unit, e, f) => (farR > 0 && farF > 0 && Math.hypot(e.x - unit.x, e.y - unit.y) > farR + 1e-9 ? f + farF : f);
+    const selfForce = (unit, e, f) => (farR > 0 && farF > 0 && hypot(e.x - unit.x, e.y - unit.y) > farR + 1e-9 ? f + farF : f);
     const pullSelf = (battle, unit, e, f) => { if (e && e.alive) dragDmg(battle, unit, e, pullToFront(battle, unit, e, selfForce(unit, e, f))); };
     return {
       skills: alt(def, {