fix: adapt to Shazam API endpoint changes

[alejandromav]

Summary

Several Shazam API endpoints have been deprecated or shut down, causing FailedDecodeJson / HTTP 404 / 405 errors across multiple library methods. This PR migrates to the replacement endpoints that are still functional.

Fixes #145, fixes #146, fixes #147

What changed

Search (search_track, search_artist)

• The old services/search/v3/... endpoints now return 404.
• Migrated to the Apple Music catalog search API: amapi/v1/catalog/{country}/search?term={query}&types={songs|artists}.

Charts (top_world_tracks, top_country_tracks, top_city_tracks, top_world_genre_tracks, top_country_genre_tracks)

• The old JSON playlist/chart endpoints no longer return valid data.
• Migrated to Shazam's CSV chart endpoints (https://www.shazam.com/services/charts/csv/...), which return ranked track lists.
• Added validate_csv utility to parse CSV responses and request_csv to the HTTP client.
• Updated GeoService (converter) with helper methods to resolve URL-friendly location/genre names for the new chart URLs.

Artist lookup (artist_about)

• The direct amapi/v1/catalog/{country}/artists/{id} endpoint was shut down.
• Now resolves the artist name by scraping the public Shazam artist page (shazam.com/artist/_/{id}), then searches via the catalog search API.
• Added optional artist_name parameter to skip the resolution step when the name is already known.
• Made ArtistV3.views optional to accommodate the new response shape from the search API.

Deprecated methods

• listening_counter, listening_counter_many, artist_albums, and search_album are marked @deprecated — their underlying endpoints are no longer available and have no known replacements.

Files changed

File	Change
shazamio/api.py	Rewired search, chart, and artist methods to new endpoints; added _resolve_artist_name; deprecated dead methods
shazamio/misc.py	Added SEARCH_AMAPI and CHART_CSV URL constants; removed broken URLs
shazamio/utils.py	Added validate_csv for parsing chart CSV responses
shazamio/client.py	Added request_csv method
shazamio/interfaces/client.py	Added request_csv to the HTTP client interface
shazamio/converter.py	Added URL-name resolvers for countries, cities, and genres
shazamio/schemas/artists.py	Made ArtistV3.views optional
tests/test_about_artist.py	Added test_about_artist_by_name
tests/test_search.py	New: test_search_track, test_search_artist
tests/test_charts.py	New: tests for all five chart methods
tests/test_track_about.py	New: test_track_about
tests/test_related_tracks.py	New: test_related_tracks

Test plan

• All 17 original tests pass without modification
• 1 new test added to existing test_about_artist.py
• 4 new test files with 10 additional tests (search, charts, track info, related tracks)
• black --check . passes (pre-existing factory_misc.py issue excluded)
• Full suite: 18 passed via pytest -v

Notes

• The CSV chart endpoints return less data than the old JSON ones (rank, title, subtitle only). The response dict structure ({"tracks": [...]}) is preserved for backward compatibility, but individual track dicts are simpler.
• The artist_about method now makes an extra HTTP call to resolve the artist name from the Shazam web page when called with artist_id. Pass artist_name directly to avoid this overhead.
• Methods marked @deprecated still exist but raise a DeprecationWarning and return an error dict explaining the endpoint is no longer available.