feat: add explicit Azure OpenAI flag and setup memory bank docs

- Add openAiUseAzure flag to force Azure OpenAI client initialization
- Add "Use Azure" checkbox in API settings UI

This change improves Azure OpenAI configuration flexibility by allowing users to explicitly opt-in to Azure client, regardless of the base URL pattern.

webview-ui/src/components/settings/ApiOptions.tsx

@@ -536,6 +536,15 @@ const ApiOptions = ({ apiErrorMessage, modelIdErrorMessage }: ApiOptionsProps) =
 							Enable streaming
 						</Checkbox>
 					</div>
+					<Checkbox
+						checked={apiConfiguration?.openAiUseAzure ?? false}
+						onChange={(checked: boolean) => {
+							handleInputChange("openAiUseAzure")({
+								target: { value: checked },
+							})
+						}}>
+						Use Azure
+					</Checkbox>
 					<Checkbox
 						checked={azureApiVersionSelected}
 						onChange={(checked: boolean) => {