fixing stuff after splitting jsons

site/src/lib/dataloader.ts

@@ -186,17 +186,24 @@ export async function loadTimeseries(
 ): Promise<Timeseries | null> {
   try {
     let url: string;
+    // Strip the leading "activities/" from timeseriesUrl so we can append it
+    // to whatever directory the detail JSON lives in.
+    const filename = timeseriesUrl.replace(/^activities\//, '');
+
     if (timeseriesUrl.startsWith('http')) {
       url = timeseriesUrl;
     } else if (detailUrl.startsWith('http')) {
-      // detailUrl is absolute — resolve timeseries relative to its directory
+      // absolute detailUrl (browser shard resolution) → same directory
       const dir = detailUrl.substring(0, detailUrl.lastIndexOf('/') + 1);
-      // timeseriesUrl is "activities/id.timeseries.json" — strip leading "activities/"
-      // because dir already ends with "activities/"
-      const filename = timeseriesUrl.replace(/^activities\//, '');
       url = `${dir}${filename}`;
     } else {
-      url = `${baseUrl}data/${timeseriesUrl}`;
+      // relative detailUrl — may be plain ("activities/{id}.json", single-user)
+      // or prefixed ("dave/_merged/activities/{id}.json", multi-user SSG prop).
+      // In both cases, resolve the timeseries file from the same directory.
+      const dir = detailUrl.includes('/')
+        ? detailUrl.substring(0, detailUrl.lastIndexOf('/') + 1)
+        : '';
+      url = `${baseUrl}data/${dir}${filename}`;
     }
     return await fetchJSON<Timeseries>(url);
   } catch {