Fix episode number arrow cascade and remove Update Ranges button

- Add isUpdatingEpisodeNumbers flag to prevent re-entrant calls
- Arrow buttons now properly cascade shifts to all subsequent episodes
- Remove Update Ranges button and associated code
- Remove DevTools auto-open for cleaner release
- Syntax validation passes

index.html

@@ -524,7 +524,6 @@
             </div>
             
             <div style="display: flex; gap: 10px; margin-top: 10px;">
-                <button id="update-ranges-btn" class="begin-mapping-btn" style="flex: 1;">Update Ranges</button>
                 <button id="begin-mapping-btn" class="begin-mapping-btn" style="flex: 1;">Begin Mapping</button>
             </div>
         </div>

main.js

@@ -49,8 +49,6 @@ function createWindow() {
     }, 1000);
   }
 
-  // Open the DevTools.
-  mainWindow.webContents.openDevTools();
 }
 
 // IPC handler for selecting directory

renderer.js

@@ -11,7 +11,6 @@ const showDetailsEl = document.getElementById('show-details');
 const progressContainer = document.getElementById('progress-container');
 const progressText = document.getElementById('progress-text');
 const progressCount = document.getElementById('progress-count');
-const updateRangesBtn = document.getElementById('update-ranges-btn');
 
 // Current state
 let currentDirectory = null;
@@ -20,6 +19,7 @@ let currentShow = null;
 let currentSeasons = [];
 let currentEpisodes = [];
 let selectedSeasonEpisodeCount = 0;
+let isUpdatingEpisodeNumbers = false;
 
 // Event Listeners
 selectDirBtn.addEventListener('click', selectDirectory);
@@ -33,13 +33,7 @@ document.addEventListener('click', function(e) {
   }
 });
 
-// Add click handler for Update Ranges button
-if (updateRangesBtn) {
-  updateRangesBtn.addEventListener('click', function() {
-    updateEpisodeNumbers();
-    checkEpisodeCountMatch();
-  });
-}
+
 
 // Add click handler for Begin Mapping button
 document.getElementById('begin-mapping-btn').addEventListener('click', beginMapping);
@@ -449,6 +443,14 @@ function handleDrop(e) {
 }
 
 function updateEpisodeNumbers() {
+  if (isUpdatingEpisodeNumbers) {
+    console.log('[updateEpisodeNumbers] Already updating, skipping re-entrant call');
+    return;
+  }
+  
+  isUpdatingEpisodeNumbers = true;
+  
+  try {
     const fileItems = fileListEl.querySelectorAll('.file-item:not(.folder-item)');
     let episodeNum = 1;
     
@@ -473,6 +475,9 @@ function updateEpisodeNumbers() {
         episodeNum = end + 1;
       }
     });
+  } finally {
+    isUpdatingEpisodeNumbers = false;
+  }
 }
 
 // Make an episode number editable for range editing