add refile like orgmode

### ⚠️ This issue respects the following points: ⚠️

- [x] This is a **enhancement/feature request**. Not a [bug or question](https://github.com/gsantner/markor/issues/new/choose).
- [x] The topic is **not** already reported at [Issues](https://github.com/gsantner/markor/issues?q=#js-issues-search). _(I've searched it and checked most recent issues)_.
- [x] Markor **is** up to date. See [Releases](https://github.com/gsantner/markor/tags) for the latest version. Updates are available from [F-Droid](https://f-droid.org/en/packages/net.gsantner.markor/) and GitHub.
- [x] The wanted feature/enhancement is not present in the latest development version (git master). (Please [download](https://nightly.link/gsantner/markor/workflows/build-android-project/master) and try the test version of Markor, named **Marder**. Don't worry; Markor and Marder appear as completely separate applications. You can install both side-by-side, and Markor's settings are not touched. If your desired feature is present, you don't need to open this issue. The change will be part of the next Markor update.)

### Description

1.Situation
I often use markor for simple GTD task management
I use todo.txt for recently to do list

2.Problem
But sometimes some item is postponed, I want to move them to other todotxt like later.todo.txt

3. Requirement
I hope current line item in note can be moved to selected note like archive，but archive only move all done item.

4. Other
I see I can delete an item for current line
Move item.
Is it possible to add a button like refile.With this button clicked , we see a pop up select file.Then the item is appended to that file and disappeared in current line.
Now I only use cut and paste by hand

### Information

Android version:
Device (phone model):
App Version:

### Source

GitHub Releases

### Format / File type

todo.txt

### Additional info / Log

```shell
-
```

The issue identifies todo.txt editing and the existing per-line delete and archive actions, but names no files or tests. Start by tracing those actions and the note/file-selection flow; done means a selected current line is appended to a chosen note and removed from the original without affecting unrelated lines.

Written by the indexing model from the issue text.