test: the e2e suite waits for each save before it closes the popup (closes #446)

The Settings round trip switched the theme and the network and closed
the popup at once. A close before the change handler's save lands loses
the switch, and the suite then ran on Sepolia.

tests/e2e/run.js now has one helper that polls a field of the stored
record until it holds the expected value, in place of the wait that
only read viewStack. Each Settings switch and spam-filter toggle waits
for its save, the recovery-phrase reopen waits for its saved view, and
reopenPopup() waits until the view it expects to reopen on is the saved
one. README.md no longer lists #446 among the open reports of the
Chrome suite failing under load.

Model: opus-5-5

README.md

@@ -619,15 +619,13 @@ The jobs **report, they do not gate.** A failure is a red mark against the
 commit that a reviewer has to account for, not a hard block: whether a check
 blocks a merge is Gitea branch protection, which this repo does not configure.
 
-That is not only a statement about configuration. Reports of the Chrome suite
-**failing under load** are still open, among them
+That is not only a statement about configuration. A report of the Chrome suite
+**failing under load** is still open:
 [#290](https://git.eeqj.de/sneak/AutistMask/issues/290), runs on a busy machine
-failing with `the extension opened no approval window within 30000ms`, and
-[#446](https://git.eeqj.de/sneak/AutistMask/issues/446), the Settings round trip
-closing the popup before its network switch is saved. So a red `e2e-chrome` has
-to be read before it is believed, and those failures are the blocker to ever
-making this a required check. Do not answer them with a retry wrapper: a suite
-that reruns until it is green stops being evidence.
+failing with `the extension opened no approval window within 30000ms`. So a red
+`e2e-chrome` has to be read before it is believed, and those failures are the
+blocker to ever making this a required check. Do not answer them with a retry
+wrapper: a suite that reruns until it is green stops being evidence.
 
 Nothing in either job can pass vacuously. There is no `continue-on-error` and no
 `|| true`; both scripts exit non-zero when docker is missing, when the image