fix: column view navigation and duplicate app instance

- Fix duplicate tsview-app rendering by checking if element already exists in HTML
- Fix column navigation to expand horizontally instead of resetting
- Remove navigate event dispatch from column folder selection to preserve column state

ts_web/elements/tsview-s3-columns.ts

@@ -186,14 +186,8 @@ export class TsviewS3Columns extends DeesElement {
       console.error('Error loading folder:', err);
     }
 
-    // Dispatch navigate event
-    this.dispatchEvent(
-      new CustomEvent('navigate', {
-        detail: { prefix },
-        bubbles: true,
-        composed: true,
-      })
-    );
+    // Note: Don't dispatch navigate event here - columns view expands horizontally
+    // The navigate event is only for breadcrumb sync, not for column navigation
   }
 
   private selectFile(columnIndex: number, key: string) {