docs(dreamcode): mention interop functionality and show code how requset parsing and the event API will work (#35)

closes #19

Author: gr2m

README.md

@@ -14,7 +14,7 @@ import { verifyRequestByKeyId } from "@copilot-extensions/preview-sdk";
 const payloadIsVerified = await verifyRequestByKeyId(
   request.body,
   signature,
-  key,
+  keyId,
   {
     token: process.env.GITHUB_TOKEN,
   }

dreamcode.md

@@ -70,13 +70,30 @@ createServer(createNodeMiddleware(copilotExtension)).listen(3000);
 copilotExtension.log.info("Listening on http://localhost:3000");
 ```
 
+For other environments, these methods are available:
+
+```js
+// verify the payload and call handlers
+await copilotExtension.verifyAndReceive({ payload, signature, keyId });
+// same, but skip verification
+await copilotExtension.receive({ payload });
+
+// and if you don't want to use the event-based API
+const { isValidRequest, payload } = await copilotExtension.verifyAndParse(
+  payload,
+  signature,
+  keyId
+);
+```
+
 ## Notes
 
 Regarding the context passed to event handlers
 
 - `message` / `confirmation` / etc are objects as received by the user
 - `octokit` is a pre-authenticated octokit instance
 - `prompt` is based on my work at https://github.com/github/gr2m-projects/blob/167/github-models/167-github-models/README.md. A simple API to interact with GitHub models. I assume we will default the prompt URL to `https://api.githubcopilot.com/chat/completions` and the model to `gpt-4o` (or whatever our CAPI name for that is?)
+- The `prompt` API will automatically apply interop transformations if the request is sent to an endpoint other than Copilot's chat complitions endpoint.
 - `respond` is an API to send different types of responses to the user
 - `log` is the logger as we use it in Octokit. See https://github.com/octokit/core.js?tab=readme-ov-file#logging