some tiny prep work for microsoft#249519 (microsoft#250863)

Author: jrieken

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

@@ -33,19 +33,19 @@ import { IChatRequestVariableValue } from './chatVariables.js';
 import { ChatAgentLocation, ChatMode } from './constants.js';
 
 interface IBaseChatRequestVariableEntry {
-	id: string;
-	fullName?: string;
-	icon?: ThemeIcon;
-	name: string;
-	modelDescription?: string;
+	readonly id: string;
+	readonly fullName?: string;
+	readonly icon?: ThemeIcon;
+	readonly name: string;
+	readonly modelDescription?: string;
 
 	/**
 	 * The offset-range in the prompt. This means this entry has been explicitly typed out
 	 * by the user.
 	 */
-	range?: IOffsetRange;
-	value: IChatRequestVariableValue;
-	references?: IChatContentReference[];
+	readonly range?: IOffsetRange;
+	readonly value: IChatRequestVariableValue;
+	readonly references?: IChatContentReference[];
 
 	omittedState?: OmittedState;
 }
@@ -83,20 +83,20 @@ export interface IChatRequestImplicitVariableEntry extends IBaseChatRequestVaria
 	readonly value: URI | Location | undefined;
 	readonly isSelection: boolean;
 	readonly isPromptFile: boolean;
-	enabled: boolean;
+	readonly enabled: boolean;
 }
 
 export interface IChatRequestPasteVariableEntry extends IBaseChatRequestVariableEntry {
 	readonly kind: 'paste';
-	code: string;
-	language: string;
-	pastedLines: string;
+	readonly code: string;
+	readonly language: string;
+	readonly pastedLines: string;
 
 	// This is only used for old serialized data and should be removed once we no longer support it
-	fileName: string;
+	readonly fileName: string;
 
 	// This is only undefined on old serialized data
-	copiedFrom: {
+	readonly copiedFrom: {
 		readonly uri: URI;
 		readonly range: IRange;
 	} | undefined;
@@ -119,7 +119,7 @@ export interface IImageVariableEntry extends IBaseChatRequestVariableEntry {
 	readonly mimeType?: string;
 }
 
-export interface INotebookOutputVariableEntry extends Omit<IBaseChatRequestVariableEntry, 'kind'> {
+export interface INotebookOutputVariableEntry extends IBaseChatRequestVariableEntry {
 	readonly kind: 'notebookOutput';
 	readonly outputIndex?: number;
 	readonly mimeType?: string;