Make two tests independent of host load (closes #256)

The home-card refresh test runs keepHomeCardsFresh in a synctest bubble,
so its waits are exact on a fake clock instead of 15-second polls.

The geo fallback subtest in which geojs never answers used a 50 ms time
limit and counted requests at the fake server, which a slow host could
miss. It now uses a transport that counts each request as it is sent and
holds it until the time limit ends it.

Model: opus-5-5

TODO.md

@@ -57,6 +57,10 @@ File an issue for each problem the run finds.
 
 # Completed Steps
 
+- 2026-11-11: two more tests no longer fail on a busy host. The test of the home
+  page's card refresh runs on a fake clock. The geo test in which geojs never
+  answers counts each request as it is sent, not when it reaches the server
+  (closes https://git.eeqj.de/sneak/routewatch/issues/256).
 - 2026-11-10: `github.com/mattn/go-sqlite3` is at v1.14.53, so building on the
   host no longer prints its two C compiler warnings (closes
   https://git.eeqj.de/sneak/routewatch/issues/245).