Drive the first-run experience in a real browser

e2e-setup-browser.sh signs a user with no organisation into the real web
console, creates a farm, copies the gateway settings the page shows,
connects a stand-in gateway configured from exactly those settings, adds a
printer through the form, gets a failed-print alert and dismisses it, then
removes the printer. Afterwards it searches every table and the backend log
for the access code the browser typed. No printer is touched and dispatch
is off. The e2e scripts that start the real proxy also give it its own store
file in the scratch directory.

scripts/e2e-edge.sh

@@ -220,6 +220,7 @@ env -C "$PROXY_DIR" \
   CONTINUUM_GO2RTC_CONFIG="$WORK/go2rtc.yaml" \
   CONTINUUM_STREAM_BASE_URL="$STREAM_BASE_URL" \
   CONTINUUM_PRINTERS_PATH=printers.toml \
+  CONTINUUM_STORE_PATH="$WORK/continuum.db" \
   RUST_LOG=info \
   "$PROXY_DIR/target/debug/continuum-proxy" > "$WORK/proxy.log" 2>&1 &
 PROXY_PID=$!