Reading an empty file results in a confusing "Input file contains unsupported image format" error

Nobody has claimed this yet.

## Possible bug

### Is this a possible bug in a feature of sharp, unrelated to installation?

- [x] Running `npm install sharp` completes without error.
- [x] Running `node -e "require('sharp')"` completes without error.

If you cannot confirm both of these, please open an [installation issue](https://github.com/lovell/sharp/issues/new?labels=installation&template=installation.md) instead.

### Are you using the latest version of sharp?

- [x] I am using the latest version of `sharp` as reported by `npm view sharp dist-tags.latest`.

If you cannot confirm this, please upgrade to the latest version and try again before opening an issue.

If you are using another package which depends on a version of `sharp` that is not the latest, please open an issue against that package instead.

### What is the output of running `npx envinfo --binaries --system --npmPackages=sharp --npmGlobalPackages=sharp`?

```
System:
OS: macOS 14.4.1
CPU: (10) arm64 Apple M1 Max
Memory: 117.39 MB / 18.00 GB
Shell: 5.9 - /bin/zsh
Binaries:
Node: 22.6.0 - ~/.local/state/fnm_multishells/85165_1734955094405/bin/node
npm: 10.8.2 - ~/.local/state/fnm_multishells/85165_1734955094405/bin/npm
npmPackages:
sharp: ^0.33.5 => 0.33.5
```

### Does this problem relate to file caching?

The default behaviour of libvips is to cache input files, which can lead to `EBUSY` or `EPERM` errors on Windows.
Use [`sharp.cache(false)`](https://sharp.pixelplumbing.com/api-utility#cache) to switch this feature off.

- [x] Adding `sharp.cache(false)` does not fix this problem.

### Does this problem relate to images appearing to have been rotated by 90 degrees?

Images that contain EXIF Orientation metadata are not auto-oriented. By default, EXIF metadata is removed.

- To auto-orient pixel values use the parameter-less [`rotate()`](https://sharp.pixelplumbing.com/api-operation#rotate) operation.
- To retain EXIF Orientation use [`keepExif()`](https://sharp.pixelplumbing.com/api-output#keepexif).

- [x] Using `rotate()` or `keepExif()` does not fix this problem.

### What are the steps to reproduce?

1. Create an empty image file `touch test.jpg`
2. Try reading it, e.g. by doing `sharp('test.jpg').toBuffer();`

File extension doesn't matter, I've tried `*.avif`, `*.png`, etc.

Result:

```
> node index.js
/Users/dmitry/Projects/sharp-empty-image/node_modules/sharp/lib/output.js:163
const stack = Error();
^

Error: Input file contains unsupported image format
at Sharp.toBuffer (/Users/dmitry/Projects/sharp-empty-image/node_modules/sharp/lib/output.js:163:17)
at Object. (/Users/dmitry/Projects/sharp-empty-image/index.js:3:19)
at Module._compile (node:internal/modules/cjs/loader:1546:14)
at Module._extensions..js (node:internal/modules/cjs/loader:1691:10)
at Module.load (node:internal/modules/cjs/loader:1317:32)
at Module._load (node:internal/modules/cjs/loader:1127:12)
at TracingChannel.traceSync (node:diagnostics_channel:315:14)
at wrapModuleLoad (node:internal/modules/cjs/loader:217:24)
at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:166:5)
at node:internal/main/run_main_module:30:49
```

### What is the expected behaviour?

Some kind of error which explicitly tells that the file is empty.

### Please provide a minimal, standalone code sample, without other dependencies, that demonstrates this problem

```js
const sharp = require('sharp');

// test.jpg must exists and be empty
sharp('test.jpg').toBuffer();
```

### Please provide sample image(s) that help explain this problem

Reproduce the empty-file case from the issue using `node index.js` and `sharp('test.jpg').toBuffer()`. Start at the reported `node_modules/sharp/lib/output.js:163` stack location, then identify the relevant input-error handling and add coverage for an explicitly empty-file error; done means the error distinguishes an empty file from an unsupported image format.

Written by the indexing model from the issue text.