rss.chat itself now runs on SQLite

This morning's note said an rss.chat server can run on SQLite; by this evening the flagship server does. Both production servers were upgraded to the new software (v0.6.0) during the afternoon, running on MySQL exactly as before -- proof that the change disturbs nothing for existing installs. Then the migration itself: export the whole database to one JSON file, set "flUseSqlite": true in config.json, import, restart. All 752 rows -- 12 users, 361 posts, 217 likes, 162 served files -- came across with their ids intact, so every permalink still works, and the Software versions dialog now reads "SQLite version: v3.49.2." The MySQL database was never written to during the switch, so rolling back would have been one config line -- it wasn't needed. Total elapsed time, including a wrong turn when an unsaved config file sent the import to the wrong engine (it stopped harmlessly on the first duplicate row): about twenty minutes. demo.rss.chat follows tomorrow.