test: load the popup's libraries once per test file, not on every boot (closes #428)

Every popup boot in the tests resets jest's module registry so that src/
loads fresh, and that also reloaded ethers, libsodium-wrappers-sumo, qrcode
and ethereum-blockies-base64 each time. tests/support/popupBoot.js now loads
those four once per test file and registers them once with jest.doMock(),
which jest.resetModules() keeps, so every boot gets the same copies. No test
or assertion changed. make test takes 8-13s on the shared build host, down
from 17-25s, measured in alternating runs before and after the change.

Model: opus-5-5

Dockerfile

@@ -8,12 +8,11 @@ WORKDIR /app
 # image sets it.
 ENV AUTISTMASK_LINT_NATIVE=1
 
-# script/test's default 30s bound is the host figure, against a suite that
-# takes 23-29s there with three jest workers. In here the same suite starts on
-# a cold jest cache and shares the runner with the rest of the build, so 30s
-# is too tight — it killed a healthy suite at 30.6s on a cold CI cache. 180s
-# still catches a hang in three minutes and cannot be tripped by a suite that
-# is merely running on contended hardware.
+# script/test's default 30s bound is the host figure. In here the same suite
+# starts on a cold jest cache and shares the runner with the rest of the build,
+# so 30s is too tight — it killed a healthy suite at 30.6s on a cold CI cache.
+# 180s still catches a hang in three minutes and cannot be tripped by a suite
+# that is merely running on contended hardware.
 ENV AUTISTMASK_TEST_TIMEOUT=180
 
 # script/bootstrap installs all prerequisites (make via apt here; node