WIP: PICARD-3113: Expand translation to album and track names

[knguyen1]

WIP: needs testing

Summary

• This is a…
  • Bug fix
  • Feature addition
  • Refactoring
  • Minor / simple change (like a typo)
  • Other
• Describe this change in 1-2 sentences: Extends name translation functionality to include album titles and track names in addition to existing artist name translation. Users can now independently toggle translation for artist names, album titles, and track titles using their preferred locales and script exceptions.

Problem

• JIRA ticket (optional): PICARD-3113

Currently, Picard only supports translating artist names to user-preferred locales. Users who want localized album and track titles must manually edit metadata or rely on external tools. This limits the usefulness of MusicBrainz's alias data for non-artist entities.

Solution

Core Changes:

• Refactored translation logic in mbjson.py into small, testable helper functions
• Added _find_localized_alias_name() to select aliases for non-artist entities (albums, tracks)
• Extended release_to_metadata() to apply album title translation from release aliases
• Extended recording_to_metadata() to apply track title translation from recording aliases
• Script exception logic now applies to album and track translations as well

Configuration:

• Added translate_album_names and translate_track_titles boolean settings
• All three translation toggles (artist/album/track) are independent and share the same locale preferences and script exception rules

UI Updates:

• Reorganized metadata options page with clearer grouping of translation controls
• Changed checkbox labels to be more concise ("Artist names", "Album titles", "Track titles")
• Updated script exception label to be generic ("Ignore name translation...")

Testing:

• Added comprehensive test suite in test_mbjson_translations.py covering helper functions and translation behavior
• Added conftest.py to provide defaulting config fixture for all tests, preventing KeyError with new settings

Action

Additional actions required:

• Update Picard documentation (please include a reference to this PR)
• Other (please specify below)

Documentation should be updated to describe the new album and track title translation options and how they interact with locale preferences and script exceptions.