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_10-aroma.js

@@ -3,6 +3,7 @@
 
 import { bodyInKeys } from '../../../body.js';
 import { num, tbb, keySet, skillActive, isSel, alt, instantKind, withDefaults } from '../shared/tier4.js';
+import { hypot } from '../../../detmath.js';
 
 /** 阿罗玛's 非首次标记 (talent 起泡性能测试): one per enemy, shared by every 阿罗玛 (PRTS 备注). */
 const AROMA_MARK = 'aroma:bubbled';
@@ -71,7 +72,7 @@ export default withDefaults({
           const lo = num(tb.min_dist, 0), hi = num(tb.max_dist, 4);
           battle.on('hit', (c) => {
             if (c.source !== unit || !c.dmg.isAttack) return;
-            const d = Math.hypot(c.target.x - unit.x, c.target.y - unit.y);
+            const d = hypot(c.target.x - unit.x, c.target.y - unit.y);
             c.dmg.mul *= 1 + ds * Math.max(0, Math.min(1, (d - lo) / Math.max(1e-6, hi - lo)));
           }, { owner: unit });
         }