Submission: immich plugin

[Christian McHugh]

Hello everyone,

I have been writing a generic plugin that connects digiKam to a 
self-hosted Immich server, and before taking it further I wanted to ask 
whether the project would be interested in it as an in-tree web-service 
plugin, alongside Piwigo and the others.

While vibe coded, it is working software and was made to allow my family 
to more easily access and edit their photos through Immich. The 
repository is at https://github.com/mchugh19/immich-digikam/tree/main 
and it currently provides:

- Import of an album or a tag's contents into a local folder.
- Export of the digiKam selection to the Immich library or album.
- Metadata round-tripping through XMP sidecars (tags, rating, caption, 
GPS), which one mechanism both applications read and write. Metadata 
edited on either side is synced onto the existing Immich asset rather 
than re-uploaded.
- Edited files are recognized as new versions of photos already in 
Immich (by name, capture time, dimensions and a pixel comparison) and 
can replace the old copy as the primary of a stack, or overwrite it, 
instead of accumulating duplicates.
- It is developed and tested against Immich 3.3.3 and digiKam 9.1, and 
it has unit tests for its pure logic plus contract tests against a stub 
server.

I use it against my own server, and I am prepared to help maintain it, 
including following Immich API changes.