fix(patch): Use Updating state; handle zero DstFiles groups

The group-apply loop was reporting InstallProgressState.Install during
krpdiff patching. Rename to InstallProgressState.Updating, which is the
correct state enum value for an in-place patch operation.

When all GroupInfos have empty DstFiles arrays (e.g. the API returned
groups without dest file metadata), the previous code initialised
TotalStateToComplete and TotalCountToDownload to 0, making the progress
bar appear stuck at 0/0. Fall back to the group count as the effective
total so the counter always reads 'n/N groups' in that case, and advance
it by one per empty group so progress is visible as they are processed.

Author: Cryotechnic

Hi3Helper.Plugin.Wuwa/Management/WuwaGameInstaller.Patch.cs

@@ -1132,9 +1132,11 @@ await _owner.TryDownloadWholeFileWithFallbacksAsync(
 
                 if (patchIndex.GroupInfos.Length > 0)
                 {
-                    currentProgressState = InstallProgressState.Install;
+                    currentProgressState = InstallProgressState.Updating;
 
-                    // Count total destination files and bytes across all groups
+                    // Count total destination files and bytes across all groups.
+                    // Fall back to group count when DstFiles are empty (e.g. API parsing
+                    // returned no dest entries) so we never report a total of 0.
                     int totalDstFiles = 0;
                     long totalPatchBytes = 0;
                     foreach (var g in patchIndex.GroupInfos)
@@ -1144,10 +1146,14 @@ await _owner.TryDownloadWholeFileWithFallbacksAsync(
                             totalPatchBytes += (long)d.Size;
                     }
 
-                    installProgress.TotalStateToComplete = totalDstFiles;
+                    // If every group has no DstFiles, fall back to the group count
+                    // so the progress counter shows "0/N groups" rather than "0/0".
+                    int effectiveTotal = totalDstFiles > 0 ? totalDstFiles : patchIndex.GroupInfos.Length;
+
+                    installProgress.TotalStateToComplete = effectiveTotal;
                     installProgress.StateCount = 0;
                     installProgress.TotalBytesToDownload = totalPatchBytes;
-                    installProgress.TotalCountToDownload = totalDstFiles;
+                    installProgress.TotalCountToDownload = effectiveTotal;
                     installProgress.DownloadedBytes = 0;
                     installProgress.DownloadedCount = 0;
                     ReportProgress();
@@ -1161,7 +1167,18 @@ await _owner.TryDownloadWholeFileWithFallbacksAsync(
 
                         var group = patchIndex.GroupInfos[groupIdx];
                         if (group.DstFiles.Length == 0)
+                        {
+                            // When the fallback total is group-based (totalDstFiles == 0),
+                            // advance the counter by 1 per group so progress is visible.
+                            if (totalDstFiles == 0)
+                            {
+                                Interlocked.Increment(ref installProgress.StateCount);
+                                Interlocked.Increment(ref installProgress.DownloadedCount);
+                                ReportProgress();
+                            }
+                            completedGroups++;
                             continue;
+                        }
 
                         // Pre-compute expected byte total for this group
                         long groupExpectedBytes = 0;