fix: resolve 404 error for CSV file downloads from export directories

The download links in the exports page template were not correctly handling
files located in timestamped export directories (export_YYYY-MM-DD_HH-MM).
This caused 404 errors when users tried to download CSV files.

Fixed by updating the template to construct proper download URLs:
- For directory exports: /download/export_2025-07-11_15-43/ratings.csv
- For individual files: /download/ratings.csv

The fix uses template logic to check if the export ID starts with 'dir_'
and builds the appropriate URL path accordingly.

Author: JohanDevl

web/templates/exports.html

@@ -213,7 +213,7 @@ <h4>
           {{if eq .Status "completed"}}
             {{range .Files}}
             <a
-              href="/download/{{.}}"
+              href="{{if contains $.ID "dir_"}}/download/{{substr $.ID 4}}/{{.}}{{else}}/download/{{.}}{{end}}"
               class="btn btn-sm btn-secondary download-btn"
               title="Download {{.}}"
             >