License as BSD-3-Clause, publish artifacts to Gitea packages too

Adds LICENSE + pyproject.toml license metadata, and extends CI to
publish the built .ndp to this repo's own Gitea generic package
registry (linked to the repo) alongside the existing pkgs.daubney.dev
upload.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018n5ffHCn5QUjpDtuWTk3fh

pyproject.toml

@@ -2,6 +2,8 @@
 name = "navidromescrobbledplugin"
 version = "0.1.0"
 requires-python = ">=3.13"
+license = "BSD-3-Clause"
+license-files = ["LICENSE"]
 dependencies = []
 
 [dependency-groups]