fix!(lua): G.GAME state survives menu+start — a previous run's won flag marks later losses as wins

[Khetnen]

Description

Starting a new run via menu + start on a long-lived instance does not fully
reset run state. We catalogued four distinct cross-run leaks, each confirmed by
replaying the identical action trace on a vanilla-faithful simulator (fresh
G.GAME every run) and diffing the full gamestate after every action.

1. G.GAME.won — after any win in the session, a later run's GAME_OVER
   loss reports won = true. 16 instances observed; e.g. seed ESVPE7W2: 696
   chips vs Amber Acorn, unambiguous loss, live gamestate won = true — leaked
   from the previous run's ante-8 win on the same instance.
   src/lua/utils/gamestate.lua:739 serializes the raw global
   (state_data.won = G.GAME.won), so the stale value flows straight to
   clients; play.lua:125 also branches on it.
2. G.GAME.last_tarot_planet — a fresh run's first Fool copied the tarot
   last used in the previous seed's run.
3. G.GAME.pool_flags — gros_michel_extinct leaked: a run that never
   owned a Gros Michel was offered Cavendish in the shop (seed LS4ECDCB).
   Extinction only rolls for owned jokers at round end, so this is
   vanilla-impossible in-run.
4. G.GAME.used_jokers key loss (mechanism unidentified, same family):
   live's shop offered j_banner while Banner sat in play (seed LS6VZ3ES) —
   impossible under the no-repeat pool. RNG forensics showed both sides drawing
   identical raw picks from the same stream; the sim resampled per no-repeat,
   live kept the duplicate, i.e. live had lost the key.

Root cause is presumably in how the run is rebuilt through the menu→start path
versus a fresh process launch (possibly SMODS-side), but balatrobot's start
endpoint is the natural place to defend against it.

Impact

This corrupts benchmark results, not just convenience:

• balatrollm runs its whole task list through long-lived instances (the
  executor's port pool starts instances once) and starts each run with
  menu+start. bot.py ends a run as won when gamestate["won"] is truthy — so
  a loss that occurs on an instance after that instance has produced any win can
  be recorded and published as a win (run_won in the leaderboard data and
  the CC0 dataset).
• Leaks 2–4 make seeded runs non-reproducible: shop and consumable outcomes
  depend on what earlier seeds did in the same instance.

Suggested Fix

In start.lua, after the run initializes, explicitly reset the leak-prone keys:
G.GAME.won = false, clear last_tarot_planet, and verify pool_flags /
used_jokers are freshly built. Alternatively (or additionally), document that
benchmark-grade data requires one process per run.

Repro bundles (action trace + both gamestates + field diff) available for every
seed cited.