distrobox-export has no host-to-container direction

**Edit:** `distrobox-host-exec(1)` does document a way to do this - *"you can symlink a command name to distrobox-host-exec and then call that command by its name"* - which I missed when filing. So the mechanism exists; what is missing is the management around it. Narrowing the request accordingly.

`distrobox-export` moves things one way only: out of a container and onto the host (`--app`, `--bin`, with `--list-apps`, `--list-binaries` and `--delete` to manage them). For the other direction there is the symlink trick, and nothing else.

The difference in ergonomics between the two directions is the point:

| | container -> host | host -> container |
|---|---|---|
| create | `distrobox-export --bin /usr/bin/foo` | symlink it yourself, in the right directory |
| list | `--list-binaries` | nothing |
| remove | `--delete` | `rm`, if you remember where you put it |
| marked as managed | `# distrobox_binary` in the wrapper | nothing |
| where it goes | `~/.local/bin`, or `--export-path` | your problem |

That last row is not a small thing: the symlink has to be somewhere the **container** has on `PATH` and the **host** does not. The shared home fails that test, and the failure is a message saying the command was not run inside a container when it was (filed as #2207). `/usr/local/bin` inside the container works, but needs root there and is lost when the container is recreated.

### What I would like

Something in the shape of the existing export, run inside the container:

```
distrobox-export --host-bin docker
distrobox-export --host-bin docker --delete
distrobox-export --list-host-bins
```

writing the symlink or wrapper into a container-only path, marked with a comment the way `--bin` marks its wrappers, so it can be listed and removed like anything else distrobox put there.

### Why it comes up

A container built for one job often needs a tool that belongs to the host and that the container should not own - in my case a development container driving the host's `docker`, with everything else about it isolated.

For docker specifically there is a neater answer that needs no bridge at all: with rootless docker, `/run/user/$UID/docker.sock` is already visible inside the container and owned by the same user, so pointing `DOCKER_HOST` at it is enough. That does not generalise to other host tools, which is why the export direction still seems worth having.

Version: distrobox 1.8.2.5, podman 5.8.4, Fedora 44.

Xem xét script distrobox-export để hiểu hiện tại nó xuất các binary và app từ container sang host như thế nào. Tính năng mới sẽ bao gồm việc thêm các flag như --host-bin, --list-host-bins và --delete cho việc export từ host vào container. Kiểm tra cách các symlink được tạo thông qua distrobox-host-exec và chúng nên được đặt ở đâu (một PATH chỉ dành cho container). Trước tiên, hãy kiểm tra logic export, sau đó thiết kế các lệnh mới để quản lý symlink theo cách tương tự, đảm bảo chúng được đánh dấu là do hệ thống quản lý và có thể được liệt kê/xóa.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.