Merge origin/next into issue-167-prune-branches

Brings in #490; the TODO.md
Completed Steps conflict keeps both entries, this branch's on top.

Model: opus-5-5

TODO.md

@@ -56,6 +56,14 @@ but the review is broader than any of them.
   `feature/show-private-key`, whose README clipboard policy section is not in
   `next`.
 
+- 2026-10-07: The Firefox end-to-end suite no longer tolerates any uncaught
+  extension error ([#487](https://git.eeqj.de/sneak/AutistMask/issues/487)). Its
+  one entry, Firefox reporting a popup promise that settled after the page
+  unloaded, had lost its cause with
+  [#275](https://git.eeqj.de/sneak/AutistMask/issues/275); the entry and the
+  code that printed tolerated errors are gone from `tests/e2e/firefox/run.js`,
+  and so is the README paragraph that described it.
+
 - 2026-10-07: The toolbar icons in `icons/` can be redrawn in the tree
   ([#378](https://git.eeqj.de/sneak/AutistMask/issues/378)): `make icons` runs
   `script/lib/icons.js`, which draws the mark and writes each PNG with node's