Fix route ordering: /search before /{asset_id}

- /api/assets/search must be registered before /api/assets/{asset_id}
  to prevent FastAPI path param from catching 'search' as an asset_id.
  Returning a 422 with array detail caused frontend to show [object Object].
- Improve error message extraction in clearAssetGps catch block.

static/index.html

@@ -2169,7 +2169,11 @@ async function clearAssetGps() {
     showToast('GPS data cleared');
   } catch (e) {
     resultEl.style.display = '';
-    resultEl.innerHTML = '<span style="color:var(--red);">' + esc(e.message) + '</span>';
+    const errMsg = (e && typeof e.message === 'string') ? e.message
+      : (typeof e === 'string') ? e
+      : (e && e.detail && typeof e.detail === 'string') ? e.detail
+      : 'Unknown error';
+    resultEl.innerHTML = '<span style="color:var(--red);">' + esc(errMsg) + '</span>';
   }
 }