web usage metadata validation

[bretth18]

Description

This PR introduces new functionality for unauthenticated Last.fm catalog lookups, improves Last.fm API request encoding, and updates the MediaRemoteAdapter dependency. It also refactors parts of the codebase for consistency and maintainability.

New Last.fm Catalog Lookup Functionality:

• Added LastFmCatalogClient.swift for unauthenticated Last.fm catalog lookups, allowing metadata validation without requiring user authentication. This is integrated into the project and build system. [1] [2] [3] [4] [5]

Last.fm API Improvements:

• Introduced LastFmRequestEncoding for proper RFC 3986-compliant query encoding, fixing issues with special characters in Last.fm API requests.
• Updated LastFmManagerDesktop.swift to use the new encoding utility for both GET and POST requests, and refactored error handling to use a unified ErrorResponse type. [1] [2] [3]

Dependency Updates:

• Switched the mediaremote-adapter dependency to a new (forked) repository and pinned it to a specific revision for improved reliability. [1] [2]

Build System and Project Configuration:

• Registered new source and test files (LastFmCatalogClient.swift, TrackMetadataResolver.swift, and their tests) in the Xcode project. [1] [2] [3] [4] [5] [6] [7] [8]
• Bumped the project version from 11 to 12. [1] [2]

Codebase Cleanup:

• Removed unused or redundant code in NowPlayingFetcher.swift to simplify music app identification logic.

How to test

• Ensure all checks pass

Author checklist

This PR:

• Satisfies a goal that is specific & clearly motivated
• Adds value in isolation (whether user-facing or sustainability-related)
• Contains a concise & easy-to-understand title + description
• Adheres to SRP by default
• Presents the best possible implementation to meet its goal, given constraints at hand