feat: close preview panels and fix homescreen refresh on env switch

- resetAllPreviewPanels now disposes panels via the openPanels Map
- HomescreenViewProvider clears _webviewView on dispose so refresh()
  no-ops safely instead of throwing "Webview is disposed" and halting
  the onDidChangeEnvironment callback

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: njb90

src/commands/previewAsset.ts

@@ -121,18 +121,10 @@ function registerPreview(context: vscode.ExtensionContext) {
 
 /**
  * Closes all open preview panels when the active environment switches.
- * Uses the tab groups API so it works regardless of the openPanels tracking state.
  */
 export function resetAllPreviewPanels(): void {
-  for (const tabGroup of vscode.window.tabGroups.all) {
-    for (const tab of tabGroup.tabs) {
-      if (
-        tab.input instanceof vscode.TabInputWebview &&
-        tab.input.viewType === "cloudinaryAssetPreview"
-      ) {
-        vscode.window.tabGroups.close(tab);
-      }
-    }
+  for (const panel of openPanels.values()) {
+    panel.dispose();
   }
 }
 

src/webview/homescreenView.ts

@@ -25,6 +25,10 @@ export class HomescreenViewProvider implements vscode.WebviewViewProvider {
   ): void {
     this._webviewView = webviewView;
 
+    webviewView.onDidDispose(() => {
+      this._webviewView = undefined;
+    });
+
     webviewView.webview.options = {
       enableScripts: true,
       localResourceRoots: [vscode.Uri.joinPath(this._extensionUri, "media")],