fix: add support for fileOpener in config.json (#911)

This PR introduces the following type:

```typescript
export type FileOpenerScheme = "vscode" | "cursor" | "windsurf";
```

and uses it as the new type for a `fileOpener` option in `config.json`.
If set, this will be used to linkify file annotations in the output
using the URI-based file opener supported in VS Code-based IDEs.

Currently, this does not pass:

Updated `codex-cli/tests/markdown.test.tsx` to verify the new behavior.
Note it required mocking `supports-hyperlinks` and temporarily modifying
`chalk.level` to yield the desired output.

codex-cli/src/components/chat/message-history.tsx

@@ -1,6 +1,7 @@
 import type { TerminalHeaderProps } from "./terminal-header.js";
 import type { GroupedResponseItem } from "./use-message-grouping.js";
 import type { ResponseItem } from "openai/resources/responses/responses.mjs";
+import type { FileOpenerScheme } from "src/utils/config.js";
 
 import TerminalChatResponseItem from "./terminal-chat-response-item.js";
 import TerminalHeader from "./terminal-header.js";
@@ -19,11 +20,13 @@ type MessageHistoryProps = {
   confirmationPrompt: React.ReactNode;
   loading: boolean;
   headerProps: TerminalHeaderProps;
+  fileOpener: FileOpenerScheme | undefined;
 };
 
 const MessageHistory: React.FC<MessageHistoryProps> = ({
   batch,
   headerProps,
+  fileOpener,
 }) => {
   const messages = batch.map(({ item }) => item!);
 
@@ -68,7 +71,10 @@ const MessageHistory: React.FC<MessageHistoryProps> = ({
                 message.type === "message" && message.role === "user" ? 0 : 1
               }
             >
-              <TerminalChatResponseItem item={message} />
+              <TerminalChatResponseItem
+                item={message}
+                fileOpener={fileOpener}
+              />
             </Box>
           );
         }}