Fix poster 404: add ^~ to /storage/ locations to override static asset regex

Nginx was serving /storage/.../*.jpg from the local filesystem instead of
proxying to MinIO because the static asset regex location (~* \.(jpg|...)$)
takes priority over plain prefix locations. Adding ^~ ensures the /storage/
and /storage-private/ prefix locations always win over regex matches.

Same root cause as the earlier 405 on thumbnail uploads.

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

nginx.conf

@@ -76,7 +76,9 @@ server {
 
     # ── MinIO storage proxy (public bucket) ────────────────────
     # Serves poster images, HLS segments, etc. with caching
-    location /storage/ {
+    # ^~ ensures this prefix takes priority over the static-asset
+    # regex that would otherwise intercept .jpg/.png requests.
+    location ^~ /storage/ {
         resolver 127.0.0.11 valid=30s ipv6=off;
         set $minio_upstream http://minio:9000;
 
@@ -94,7 +96,7 @@ server {
     }
 
     # ── MinIO storage proxy (private bucket -- for HLS key delivery) ─
-    location /storage-private/ {
+    location ^~ /storage-private/ {
         resolver 127.0.0.11 valid=30s ipv6=off;
         set $minio_upstream http://minio:9000;