Further reduce chunk size to 256KB for better nginx compatibility

The 512KB chunks were still too large for some nginx configurations.
Reduced to 256KB to ensure compatibility with restrictive
client_max_body_size settings.

app/templates/main/fixture_detail.html

@@ -558,7 +558,7 @@
             return fetch(buildUrl(path), options);
         }
         
-        const CHUNK_SIZE = 512 * 1024; // 512KB chunks (smaller for nginx compatibility)
+        const CHUNK_SIZE = 256 * 1024; // 256KB chunks (smaller for nginx compatibility)
         let activeUploads = new Map();
 
         function uploadFileInChunks(file, matchId) {

app/templates/main/match_detail.html

@@ -791,7 +791,7 @@
         }
 
         // ZIP Upload Functions
-        const CHUNK_SIZE = 512 * 1024; // 512KB chunks (smaller for nginx compatibility)
+        const CHUNK_SIZE = 256 * 1024; // 256KB chunks (smaller for nginx compatibility)
 
         function uploadFileInChunks(file, matchId) {
             const totalChunks = Math.ceil(file.size / CHUNK_SIZE);

app/templates/upload/zip.html

@@ -155,7 +155,7 @@
             return fetch(buildUrl(path), options);
         }
         
-        const CHUNK_SIZE = 512 * 1024; // 512KB chunks (smaller for nginx compatibility)
+        const CHUNK_SIZE = 256 * 1024; // 256KB chunks (smaller for nginx compatibility)
 
         function uploadFileInChunks(file, matchId) {
             const totalChunks = Math.ceil(file.size / CHUNK_SIZE);