tfil heat/pillar A/B: record the owner's decision to keep the virtual pillar removed

docs/tfil_heat_pillar_ab.md

@@ -1,5 +1,22 @@
 # TFIL heat-time bullet model + virtual-pillar removal — LIVE A/B (negative)
 
+> ## DECISION — the virtual centre pillar STAYS REMOVED
+>
+> **Decided by the bot's owner on 2026-09-25, after this A/B.** The recommendation
+> below ("revert the default to pillar-ON") was **NOT adopted**. Rationale, in the
+> owner's terms: the pillar is an *invented* hazard with no physical object behind
+> it, and this test cannot distinguish "no benefit" from "small benefit" — the
+> pillar contrast is **inside the minimum detectable effect** (32.6 dmg/run,
+> 1.22 wins/run at n=10), and the raised damage-taken point estimate (p=0.040) is
+> not corrected for the multiple arms tested.
+>
+> **So: do not "fix" this by reverting.** The shipped default keeps
+> `PillarHotness = 0.0` / `PillarRadiance = 0.0`; `TR_TFIL_PILLAR_ON=1` restores the
+> old field for any future experiment. If someone later wants to reverse this
+> decision, it needs **its own pre-registered A/B at a sample size that can actually
+> resolve a contrast this small** — not a re-reading of this one.
+
+
 **Question.** Two movement changes shipped in HEAD — (a) the time-indexed bullet
 heat (`TR_TFIL_HEAT_TIME`, job j105) and (b) the removal of the invented virtual
 centre pillar (`TR_TFIL_PILLAR_ON=1` restores it, job j106) — judged on
@@ -241,7 +258,7 @@ Nothing beats it: it is the best arm on damage/run (287) and round wins
 
 * **Heat-time: keep it OFF (as shipped).** The default is already off (`fca8993`);
   no action needed, and `TR_TFIL_HEAT_TIME=1` at any tested tau should stay off.
-* **Pillar removal: the shipped default should be REVERTED.** The shipped default
+* **Pillar removal: this test recommends reverting the default** — see the **DECISION** banner at the top of this document: the owner **overruled** this recommendation and the pillar **stays removed**. The shipped default
   since `d0750ab` is `pillaoff`; it does **not** beat `old` on any verdict metric
   and is directionally worse on all three (Δdamage −5.7, Δwins −0.5, Δdamage
   taken +30.8). This is a decision for the user: restore the pre-change default