Fix Language Models UI not refreshing on group add/remove (#309495)

The Language Models view did not auto-update when:
- Adding a BYOK model with an invalid configuration (error status)
- Removing a BYOK model group

Root cause: _resolveAllLanguageModels only checked model cache changes
to decide whether to fire onDidChangeLanguageModels. When groups were
added/removed but the model set didn't change (e.g., groups with errors
or empty groups), the event never fired and the UI stayed stale.

Fixes:
1. Add _hasGroupStructureChanged to detect group-level changes (count,
   names, statuses) independently of model cache changes
2. Add explicit viewModel.refresh() after delete action, matching the
   pattern already used by the managementCommand path
3. Await configureLanguageModelsProviderGroup in addModelsForVendor and
   refresh the view model after the add flow completes

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: pierceboggan

src/vs/workbench/contrib/chat/browser/chatManagement/chatModelsWidget.ts

@@ -772,6 +772,7 @@ class ActionsColumnRenderer extends ModelsTableColumnRenderer<IActionsColumnTemp
 						return;
 					}
 					await this.languageModelsService.removeLanguageModelsProviderGroup(vendorEntry.vendor.vendor, vendorEntry.group.name);
+					this.viewModel.refresh();
 				}
 			}));
 		} else if (vendorEntry.vendor.managementCommand) {
@@ -1336,7 +1337,8 @@ export class ChatModelsWidget extends Disposable {
 	}
 
 	private async addModelsForVendor(vendor: ILanguageModelProviderDescriptor): Promise<void> {
-		this.languageModelsService.configureLanguageModelsProviderGroup(vendor.vendor);
+		await this.languageModelsService.configureLanguageModelsProviderGroup(vendor.vendor);
+		await this.viewModel.refresh();
 	}
 
 	public layout(height: number, width: number): void {

src/vs/workbench/contrib/chat/common/languageModels.ts

@@ -926,6 +926,7 @@ export class LanguageModelsService implements ILanguageModelsService {
 				}
 			}
 
+			const oldGroups = this._modelsGroups.get(vendorId) ?? [];
 			this._modelsGroups.set(vendorId, languageModelsGroups);
 			const oldModels = this._clearModelCache(vendorId);
 			let hasChanges = false;
@@ -941,6 +942,12 @@ export class LanguageModelsService implements ILanguageModelsService {
 			this._logService.trace(`[LM] Resolved language models for vendor ${vendorId}`, allModels);
 			hasChanges = hasChanges || oldModels.size > 0;
 
+			// Also detect group structure changes (added/removed groups, status changes)
+			// so the UI updates even when individual models haven't changed
+			if (!hasChanges) {
+				hasChanges = this._hasGroupStructureChanged(oldGroups, languageModelsGroups);
+			}
+
 			// Update per-model configurations for this vendor
 			this._clearModelConfigurations(vendorId);
 			for (const [identifier, config] of perModelConfigurations) {
@@ -957,6 +964,24 @@ export class LanguageModelsService implements ILanguageModelsService {
 		});
 	}
 
+	private _hasGroupStructureChanged(oldGroups: readonly ILanguageModelsGroup[], newGroups: readonly ILanguageModelsGroup[]): boolean {
+		if (oldGroups.length !== newGroups.length) {
+			return true;
+		}
+		for (let i = 0; i < oldGroups.length; i++) {
+			const oldGroup = oldGroups[i];
+			const newGroup = newGroups[i];
+			if (oldGroup.group?.name !== newGroup.group?.name
+				|| oldGroup.group?.vendor !== newGroup.group?.vendor
+				|| oldGroup.status?.message !== newGroup.status?.message
+				|| oldGroup.status?.severity !== newGroup.status?.severity
+				|| oldGroup.modelIdentifiers.length !== newGroup.modelIdentifiers.length) {
+				return true;
+			}
+		}
+		return false;
+	}
+
 	getLanguageModelGroups(vendor: string): ILanguageModelsGroup[] {
 		return this._modelsGroups.get(vendor) ?? [];
 	}