Parts of deployment docs missing?

## Problem Description

I've tried setting up safe-settings with my own deployment, following the Deploy documentation.
I've got most things set up, but in the steps for setting up the [Github App](https://github.com/github/safe-settings/blob/main-enterprise/docs/deploy.md#create-the-github-app), not using manifest flow (which I don't understand how I would use), it says:

> Webhook URL: Use https://example.com/ for now, we'll come back in a minute to update this with the URL of your deployed app.

But then the Webhook URL is never talked about again in the rest of the document.

I've tried setting it to the root of my deployed application, but that doesn't seem to work.

### What is actually happening

From the App logs, I can see that the App responds with 404 when it gets POSTs to `/`.

### What is the expected behavior

I expected the POSTs to get handled in some way, triggering the App to do it's work.

### Error output, if available

I pulled this from the logs, and removed a lot of things I don't think are relevant. I've also redacted some IDs I figured might be sensitive in nature.

```
{
"level": 30,
"time": 1768505477810,
"pid": 25,
"hostname": "safe-settings-5468976d78-wz92r",
"name": "probot",
"req": {
"_parsedUrl": {
"_raw": "/",
"auth": null,
"hash": null,
"host": null,
"hostname": null,
"href": "/",
"path": "/",
"pathname": "/",
"port": null,
"protocol": null,
"query": null,
"search": null,
"slashes": null
},
"method": "POST",
"originalUrl": "/",
"params": {},
"query": {},
"rawHeaders": [
"host",
"safe-settings.ibidem.no",
"user-agent",
"GitHub-Hookshot/47f175b",
"content-length",
"21206",
"accept",
"*/*",
"content-type",
"application/json",
"x-github-delivery",
"",
"x-github-event",
"pull_request",
"x-github-hook-id",
"",
"x-github-hook-installation-target-id",
"",
"x-github-hook-installation-target-type",
"integration",
"x-hub-signature",
"sha1=bc9f858ade2a2203164048267afe61f0bb5ec6ea",
"x-hub-signature-256",
"sha256=12d6cdb2d5049d231c23489608a457e536c386a95ba563f729a7b9251dd20b1c",
"x-forwarded-proto",
"https",
"x-forwarded-for",
"10.42.5.0"
],
"url": "/"
},
"res": {
"_header": "HTTP/1.1 404 Not Found\r\nX-Powered-By: Express\r\nContent-Security-Policy: default-src 'none'\r\nX-Content-Type-Options: nosniff\r\nContent-Type: text/html; charset=utf-8\r\nContent-Length: 140\r\nDate: Thu, 15 Jan 2026 19:31:17 GMT\r\nConnection: keep-alive\r\nKeep-Alive: timeout=5\r\n\r\n",
"statusCode": 404,
"statusMessage": "Not Found"
},
"responseTime": 94,
"msg": "POST / 404 - 94ms"
}
```

## Context

### Are you using the hosted instance of probot/settings or running your own?

Running my own

### If running your own instance, are you using it with github.com or GitHub Enterprise?

With github.com

#### Version of probot/settings

v0.1.0-rc.26 according to the App frontpage when visisted with browser.

#### Version of GitHub Enterprise

N/A