Fix proxy icon support

[rgov]

Native document-based applications on macOS will use a "proxy icon" that shows where the file is on the filesystem, and can be dragged to other applications (for instance, if you wanted to attach it to an email). It would be nice for Studio to support them, if Electron provides a way.

[jtbandes]

We already do this: https://github.com/foxglove/studio/blob/2fc162bd50c9f301b291178ce4ecbc4cf4aee9eb/desktop/main/index.ts#L173

It looks like a bug that the IterablePlayer does not set its _filePath.

https://github.com/foxglove/studio/blob/979f37d8fef2866425da7574bae523f7e8de7a77/packages/studio-base/src/players/IterablePlayer/IterablePlayer.ts#L104

[defunctzombie]

I've long wondered what this file path setting is for or about! I'll take care of this.

[jtbandes]

This behavior was broken in https://github.com/foxglove/studio/commit/6d0e744df4581b5c97f1497d5c32c762bab34977#diff-8ff00f03f90dedeb147ca074f56cdc45867c552e8383a6c10710c7843ed1f7ceL30

[defunctzombie]

Upon further investigation this behavior was broken before these changes (likely with the changes to add recents list). The handles we use to work with files in the app don't have a reference to the original file path:

https://github.com/electron/electron/issues/33647

[jtbandes]

We've explored a direct fix by adding this path feature for FileSystemHandle (https://github.com/electron/electron/pull/35604), but the Electron team is not interested in accepting this patch and would like to see a different approach. So this doesn't really fit as a bug here — more of a feature request that is blocked on upstream support (https://github.com/electron/electron/issues/33647).