j145 TFIL: a turn-cost tiebreak among the SAFE tiles (default-off)

The picker scored candidates on pathMaxHeat alone and then drew uniformly
among the survivors, so a mirror-side tile was as likely as a straight-ahead
one. Added a continuous turn cost as a DRAW WEIGHT applied only after the
hard heat filter:

  w = max(1, round(1 + TR_TFIL_TURN_BIAS * (1 - max(0,|turn| - REF)/180)))

- TR_TFIL_TURN_BIAS (default 0) is the odds ratio straight-ahead vs 180 deg;
  TR_TFIL_TURN_REF_DEG (default 45) is where the penalty starts. Both
  default-off-effect: the default-path golden in test_tfil_commit_env.nim is
  unchanged and still passes.
- Turn cost is NEVER folded into the heat score. The filter stays hard.
- The draw stays random (j51 measured an argmin worse); every weight is
  floored at 1, so the pool can never be emptied and bias 0 is exactly the
  shipped uniform draw.
- |turn| now travels on the ScoredTile, and the commit log gained turn /
  minturn / promote so a caller can measure the regret of the draw.

Guards: 51 -> 66 checks (an absurd 99:1 bias never rescues an over-threshold
tile; mean |turn|, draw regret, >90 and mirror-side shares all fall; path
heat does not rise). env_report + .env.example updated.

ModularBot_garage/.env.example

@@ -114,6 +114,8 @@ TR_TFIL_COMMIT_LOG=     # path for the per-commit log; empty = no log
 TR_TFIL_COMMIT_ARRIVAL=off   # on = hold the dodge tile until we are ON it (not a fixed dwell)
 TR_TFIL_COMMIT_MARGIN=0.0    # lava an alternative tile must be cooler by before it wins the tile
 TR_TFIL_NOREV_SPEED=0.0      # px/tick; below this, a mid-flight switch may not turn the bot around
+TR_TFIL_TURN_BIAS=0.0    # turn TIEBREAK odds ratio among SAFE tiles; 0 = uniform draw as today
+TR_TFIL_TURN_REF_DEG=45.0   # deg; turn below which the tiebreak applies no penalty
 TR_TFIL_HEAT_TIME=off   # on = index bullet heat by time (flat field when off)
 TR_TFIL_HEAT_TAU=9.0    # ticks a tracked bullet's heat lives for
 TR_TFIL_HEAT_POWER_GAIN=1.0  # scale of the heat a bullet paints, per firepower