smoketest: say once a minute that a command in the VM is still running

run_in_vm prints how long it has run and the log's latest line, so an
hour-long install.sh shows progress without tail -f.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/smoketest.bats

@@ -138,6 +138,14 @@ upstream_main() {
   [ -f "$SMOKETEST_RESULTS/02-second.log" ]
 }
 
+@test "run_in_vm says once a tick that it's still running, with the log's latest line" {
+  export SMOKETEST_TICK=1
+  run run_in_vm slow 'echo working; sleep 2.5'
+  [ "$status" -eq 0 ]
+  [[ "$output" == *"  still running slow (0 min): working"* ]]
+  [[ "$output" == *"== slow exited 0 (log: "* ]]
+}
+
 @test "run_in_vm writes its log while the script runs" {
   run_in_vm slow 'echo early; cat "$SMOKETEST_RESULTS/01-slow.log" > "$HOME/seen"'
   [ "$STATUS" -eq 0 ]