docs: record an intermittent browser test failure

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

ROADMAP.md

@@ -357,6 +357,11 @@ charges. Fix as part of 1.1.
   table and the packer so 3.2 has somewhere to land.
 - `[ ]` 5.7 — Commercial rules duplicated between `FAIXAS` (JS) and `TIERS` (Python)
   `(F26)`. `test_pricing` guards parity; generate one from the other instead.
+- `[ ]` 5.9 — `local/browser_test.mjs` failed once and passed on an immediate
+  re-run, with no code change in between (2026-09-21). It is a deploy gate when the
+  runner has Chrome, so an intermittent failure there blocks releases for no reason.
+  Suspect Chrome startup timing or a race against stack readiness. Watch it, and if
+  it recurs add an explicit readiness wait rather than a retry.
 - `[ ]` 5.8 — The Site promises retention the system does not honour. The cart aside
   still reads *"O arquivo fica guardado por 90 dias e o histórico do pedido por 12
   meses"*, while `CONTEXT.md` and the implemented retention are 30 days maximum.