Rewrite on simdjson with a flat src and smack-style build

web/pre.js

@@ -0,0 +1,9 @@
+// Keeps the prefs folder (/libsdl, where SDL puts it on the web) in IndexedDB, loading it before the game starts so
+// settings and saves are there when it reads them. The game writes it back after every save.
+Module.preRun = Module.preRun || [];
+Module.preRun.push(() => {
+    FS.mkdir("/libsdl");
+    FS.mount(IDBFS, {}, "/libsdl");
+    addRunDependency("prefs");
+    FS.syncfs(true, () => removeRunDependency("prefs"));
+});