chore(tools): drop one-shot PSR-4 migrators after apply

Remove psr4-migrate.php / psr4-fix-multi.php (mass file rewriters that
triggered AV false positives on merge). Migration is complete; keep
build-psr4-map inventory only and note this in the ADR.

tools/adr-classes-domain-placement.md

@@ -53,8 +53,8 @@ Domain folders were frozen after the root→domain move. Theme types then migrat
 
 ### Map tooling
 
-- `php tools/build-psr4-map.php --write` — inventory / map under `tools/psr4-map/`
-- Migration helpers under `tools/psr4-*.php` (historical; re-run only with care)
+- `php tools/build-psr4-map.php --write` — read-only inventory / map under `tools/psr4-map/`
+- One-shot mass-rewrite migrators are **not** kept in-tree (completed migration; AV false positives on file-tree rewriters)
 
 ## Out of scope