[Store Plugin] Open Calibre Store

[Ketzah]

The plugin aims to add a store function to Calibre for adding networked or remote Calibre OPDS servers as a searchable store.

Basic Features:
- Searches multiple Open Calibre servers
- Works with LAN libraries
- Supports IP addresses and hostnames
- HTTP and HTTPS support
- Basic authentication support
- OPDS feed parsing
- Duplicate result filtering
- Book downloads through Calibre

Configuration:
In the plugins, the customize plugin allows you to save the servers and also has an option to test. When testing, it uses the IP: port to verify OPDS access to make sure it's available; otherwise, it times out
(you can test it outside this function by just going to the IP: port in your browser and seeing if Calibre displays)

Usage:
Once servers have been added, you can configure it in "Get books" to use the
"Open Calibre Store". After doing that, it will search networked/remote servers for specific books/authors/keywords; if the remote server has matches, they will be displayed. From there, you can download or show in store. When downloading, it will prompt for format if the network/remote server has multiple formats. Show in store will take you to the book detail OPDS page for the book on the network/remote server. When downloading, it will also pull metadata from the server if available.

Remarks:
I've only tested it on Calibre OPDS, not any other OPDS systems.
Tested in Version:9.12.0 on Windows.
I've set a tentative requirement of Version: 9.0.0.
I've not tested password-protected OPDS servers, but I did build a basic function to handle it.
Plugin tested and working as of 8/6/26.

Disclosure:
AI was used to debug and troubleshoot issues.
I will not be providing Open Calibre OPDS servers for use with this plugin.

Todo: (Would be nice, provided I get time.)
Add a bulk server add/test to customize.
Retest existing servers in list and remove inaccessible ones

Feel free to leave feedback.