Use fragments instead of query params

Permalinks now just stick the base64 string into the
fragment portion of the URL, rather than using a
query parameter. This should reduce spam in the server
logs, and also keep scenes more private.

macrovision.js

@@ -3002,7 +3002,15 @@ document.addEventListener("DOMContentLoaded", () => {
 
     unitSelector.addEventListener("input", selectNewUnit);
 
-    param = new URL(window.location.href).searchParams.get("scene");
+    param = window.location.hash;
+
+    // we now use the fragment for links, but we should still support old stuff:
+
+    if (param.length > 0) {
+        param = param.substring(1);
+    } else {
+        param = new URL(window.location.href).searchParams.get("scene");
+    }
 
     document.querySelector("#world").addEventListener("mousedown", e => {
         // only middle mouse clicks
@@ -4418,7 +4426,7 @@ function b64DecodeUnicode(str) {
 
 function linkScene() {
     loc = new URL(window.location);
-    const link = loc.protocol + "//" + loc.host + loc.pathname + "?scene=" + b64EncodeUnicode(JSON.stringify(exportScene()));
+    const link = loc.protocol + "//" + loc.host + loc.pathname + "#" + b64EncodeUnicode(JSON.stringify(exportScene()));
     window.history.replaceState(null, "Macrovision", link);
     try {
         navigator.clipboard.writeText(link);