refactor: rename to car-file-fetcher

avoid confusion with https://www.npmjs.com/package/@helia/verified-fetch

examples/car-file-fetcher/.gitignore

@@ -0,0 +1,2 @@
+car-file-fetcher
+hello.txt

examples/car-file-fetcher/README.md

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+# CAR File Fetcher
+
+This example shows how to download a UnixFS file from a gateway that implements
+[application/vnd.ipld.car](https://www.iana.org/assignments/media-types/application/vnd.ipld.car)
+responses of the [Trustles Gateway](https://specs.ipfs.tech/http-gateways/trustless-gateway/)
+specification, in a trustless, verifiable manner.
+
+It relies on [IPIP-402](https://specs.ipfs.tech/ipips/ipip-0402/) to retrieve
+the file entity via a single CAR request with all blocks required for end-to-end
+verification.
+
+## Build
+
+```bash
+> go build -o fetcher
+```
+
+## Usage
+
+First, you need a gateway that complies with the Trustless Gateway specification.
+In our specific case, we need that the gateway supports both the CAR file format.
+
+As an example, you can verifiably fetch a `hello.txt` file from IPFS gateway at `https://trustless-gateway.link`:
+
+```
+./fetcher -g https://trustless-gateway.link -o hello.txt /ipfs/bafkreifzjut3te2nhyekklss27nh3k72ysco7y32koao5eei66wof36n5e
+```
+
+## Additional learning
+
+For the sake of simplicity, this example does not support downloading UnixFS directories.
+
+See [`extract.go`](https://github.com/ipld/go-car/blob/master/cmd/car/extract.go)
+file from `go-car` in order to understand how to convert a directory into a file system.