Fix debug upload persistence and UX; exclude prod audit log from DB restore

Uploads and fixes now bust browser cache via file-mtime keys in API
responses. Debug upload shows a centered loading overlay and blocks search
while uploading. Prod DB restore skips curator_audit_log.

Co-authored-by: Cursor <cursoragent@cursor.com>

client/src/components/ArtistBio.css

@@ -1,4 +1,5 @@
 .artist-bio {
+  position: relative;
   min-height: 100vh;
   background: linear-gradient(180deg, #1a1a2e 0%, #16213e 100%);
   color: #e8d5b5;