@mseaton was spot on. I downloaded openmrs-standalone-1.12.0-beta.zip from sourceforge, unzipped it, did my jenv local 1.7 trick to run as Java 7, executed java -jar openmrs-standalone.jar, and selected demonstration mode. No concepts.
Going to Administration > Maintenance > Search Index and clicking Rebuild Search Index did the trick.
If I were to create a ticket to automatically trigger indexing on first run, does that belong in core (trunk), platform, or just the standalone (i.e., where would the fix be needed)? It’s definitely needed in the standalone, but I could see triggering the index as one of the last steps of installation (initial run) that might apply beyond just the standalone.