fix(training): make policy evaluation portable

TRAINING.md

@@ -139,6 +139,14 @@ appends to `training/eval_history.json` — the long-term progress record.
 Evaluate each new candidate against the previous promoted bot and a fixed
 early reference to see absolute progress over time.
 
+The evaluator launches Godot with the explicit headless display driver,
+Compatibility renderer, dummy audio driver, and a temporary writable log path
+so evaluation is reproducible on machines where the default renderer or
+`user://` log location is unavailable. A two-seed smoke check on 2026-09-01
+completed 10 paired episodes per seed for the current Stage 6 export versus
+`hard.json` (both runs finished 3–5 with 2 draws); this is only a runtime
+smoke and is not promotion evidence for the Stage 6 gate.
+
 If a model was trained with the locomotion mask on (curriculum stages 1, 2,
 and 5 — see below), pass `--grounded-a`/`--grounded-b` for whichever side it's on.
 The eval otherwise runs `AIShipController` fully unmasked regardless of how a