One generator, so a citation names one fight (R-265)

tools/playthrough.mjs exists to show a reader why a measured number is what it is. I cited
it to another session — read seed 2, see the wipe the 45% row is made of — and the
reproduction failed in front of them. They reported different outcomes at both seeds and
guessed the cause correctly from outside: the two tools were not drawing from the same
stream.

They were not. simulate.mjs used a private mulberry32 makeRng; playthrough.mjs had its own
LCG written to look like it. Both deterministic, both reproducible alone, and "seed 2"
named a different fight in each — which breaks the only thing the tool is for. Its own
comment claimed a seed here names the same fight there. check-focus carried a third copy of
that LCG, so the two guards described the same game with different dice.

makeRng is exported and both files use it. A playthrough seed is now exactly the first
fight of simulate.mjs --seed <n>: --runs 1 --seed 2 and the playthrough give 9 rounds, 4 of
4 down, 1 dead, both.

The other half was my citation rather than the code: the command I sent omitted --mode, so
it plays both targeting arms and prints two fights. They read the last line, I quoted the
first. The summary line now names the arm.

check-focus re-recorded under the shared stream; figures move a point or two. What it buys
is that the bimodality analysis now reproduces the published means exactly — 2.31, 3.03,
0.40, 0.42 against the four rows CLEAN GROUND publishes. Under the old LCG it agreed to
within a decimal, which looked like corroboration and was two experiments landing near each
other.

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

README.md

@@ -187,12 +187,12 @@ check-kits: OK — 25 roles, 10 trades, 218 catalogue items, every kit key resol
 check-lang: OK — en.json, 1018 keys, no leaf/branch collisions
 check-templates: OK — 19 templates compile
 check-behaviour: OK — 76 behavioural tests
-check-scenarios: OK — 12 scenario files, 79 mechanic tags, every skill named resolves against 62 catalogue entries
-check-rollable: OK — 78 rolls across 12 scenario files, every one reachable at 25% or better by somebody present
+check-scenarios: OK — 13 scenario files, 80 mechanic tags, every skill named resolves against 62 catalogue entries
+check-rollable: OK — 79 rolls across 13 scenario files, every one reachable at 25% or better by somebody present
 check-creatures: OK — 102 actor specs across 8 sources, every characteristic, skill, kit key, talent, species and style resolves, no duplicate keys
 check-anatomy: OK — 5 body plans, 36 locations, d20 complete in both modes, every location drawn, every kind handled and destructible, 20 plan changes carried 432 wounds with their severity intact, 1 flyer(s) with a survivable landing
 check-lethality: OK — 47 creatures, every one fighting exactly as recorded against the frozen party
-check-focus: OK — focus fire measured against 30 packs, helps in all of them, 28 of them by more than their own noise
+check-focus: OK — focus fire measured against 31 packs, helps in all of them, 31 of them by more than their own noise
 check-bestiary: OK — 47 creatures, the document matches the game
 ```
 <!-- guards:end -->