Moving recordings between servers

I previously ran the Docker version of Channels, but decided to run it on my ShieldTV instead. I've been running it this way for a couple of months, but had been mostly watching TV through Philo except for a few shows. Channels seems much slower to skip commercials and such than the Docker version, but that's only become an issue now that I've cancelled Philo and switched back to an HDHomeRun using Xfinity. There are about 7 recordings that I'd like to move over from the ShieldTV to the Docker version. I can copy the files over fine, but I've been moved back over to the Docker version for a week or two and have a number of recordings there as well, so a simple DB backup/restore won't work unless I don't mind losing the other recordings.

Is there any way to get the recordings re-processed by Channels (commercial skipping, etc)?

Unfortunately you cannot "import" recordings into Channels, even from another instance; you can only restore from a backup, but that restores the entire backup and wipes out the existing data.

If the metadata for the recording is no longer available, I could see that being a problem.

Any chance that there will ever be a way to add entries to the DB via a web interface (with your own custom metadata), link that to a file, and run comskip against it? (I think all this was possible with add-ons with SageTV - the program I used years ago)

In the near future, unlikely. Down the road, perhaps, as Channels shouldn't have a problem parsing their own database format to allow for merging/managing multiple databases. (However, that would probably be far down the road, as it's a pretty niche request. The only reason I foresee it making it into a release is if there are reasons for the developers to need such a feature for themselves ...)