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/op-haak.js

@@ -50,6 +50,7 @@
 import { num, talentBb, moduleBb, moduleOn, skillRec, statBuff, toggleBuff, up } from '../shared/tier1.js';
 import { toLocal } from '../../../dir.js';
 import { COLS } from '../../../constants.js';
+import { hypot } from '../../../detmath.js';
 
 const S1 = 'skchr_haak_1';
 const S2 = 'skchr_haak_2';
@@ -80,7 +81,7 @@ export function frontAlly(battle, unit, heal = false) {
     if (heal && (a.s.flags.noHeal || a.s.flags.healFree || a.profile?.noHeal)) continue;
     const dr = a.tileR - unit.tileR, dc = a.tileC - unit.tileC;
     const [lr, lc] = toLocal(dr, dc, unit.dir);
-    const k = [lr === 0 && lc > 0 ? 0 : 1, Math.hypot(dr, dc), -(a.s.taunt || 0), -(a.aggroSeq || a.deploySeq || 0), a.id];
+    const k = [lr === 0 && lc > 0 ? 0 : 1, hypot(dr, dc), -(a.s.taunt || 0), -(a.aggroSeq || a.deploySeq || 0), a.id];
     let less = !bk;
     for (let i = 0; !less && i < k.length; i++) {
       if (k[i] === bk[i]) continue;