Request: offer more options for when you drag&drop files into ScrCpy window

- [V ] I have checked that a similar [feature request](https://github.com/Genymobile/scrcpy/issues?q=is%3Aopen+is%3Aissue+label%3A%22feature+request%22) does not already exist.

**Is your feature request related to a problem? Please describe.**
A bit. Just saving more time in handling things.

**Describe the solution you'd like**
1. Offer a way to avoid installing APK files when dropping them into the window. Maybe by using CTRL while dragging.
2. Offer a way to open the file after it was copied. Maybe by using ALT while dragging.
3. In addition to the auto-installation of APK files, also offer APKS/XAPK/APKM files, which are zipped files that contain the split APK files.

Maybe the various options could be available by using right-click dragging, as it would offer a context menu like when doing it in Explorer itself (right-click dragging a file from one folder to another allows copying, moving and creating a shortcut to it).

**Describe alternatives you've considered**
The alternative for just copying the APK file is to zip it and then drag, or to use adb, or to use the file-explorer.
For the rest, it's copying and then handling on the device.

No file or test is identified. Start by locating the existing drag-and-drop handling and APK installation behavior, then determine how modifier keys or a context menu should select copying, opening, or installation. Done means the requested APK, APKS, XAPK, and APKM workflows work consistently without disrupting current drag-and-drop behavior.

Written by the indexing model from the issue text.