fix: backslash path splitting bug in ConfigPatcher

Root cause: the separator check used '\\\\'.equals(sep) comparing a
2-char Java string literal to a 1-char substring result — always false.
This caused backslash paths (C:\FALLOUT1\MASTER.DAT) to never be split
into components, so stale prefixes were never detected or rewritten.

Fix: use char comparison (sep == '\\') which correctly identifies the
separator type. Affected both findReplacement and existsIgnoreCase.

This was a pre-existing bug from the original UploadResource code that
was carried over during the refactor. Re-uploading Fallout after this
fix will correctly patch FALLOUT.CFG paths.

src/main/java/com/dostalgia/ConfigPatcher.java

@@ -86,10 +86,10 @@ public class ConfigPatcher {
 
     private static String findReplacement(String fullPath, Path extractDir, Set<String> seenPrefixes) {
         String drivePrefix = fullPath.substring(0, 2);
-        String sep = fullPath.substring(2, 3);
+        char sep = fullPath.charAt(2);
+        String splitRegex = sep == '\\' ? "\\\\" : "/";
         String relPath = fullPath.substring(3);
-        String splitter = "\\\\".equals(sep) ? "\\\\\\\\" : "/";
-        String[] parts = relPath.split(splitter, -1);
+        String[] parts = relPath.split(splitRegex, -1);
 
         for (int skip = 0; skip < parts.length; skip++) {
             StringBuilder suffix = new StringBuilder();
@@ -122,8 +122,8 @@ public class ConfigPatcher {
     }
 
     private static boolean existsIgnoreCase(Path base, String relativePath) {
-        String sep = relativePath.contains("\\") ? "\\\\\\\\" : "/";
-        String[] parts = relativePath.split(sep, -1);
+        char sep = relativePath.contains("\\") ? '\\' : '/';
+        String[] parts = relativePath.split(sep == '\\' ? "\\\\" : "/", -1);
         Path current = base;
         try {
             for (int i = 0; i < parts.length; i++) {