Spotify: Batch Spotify spotifysync API calls

[arsaboo]

This changes the Spotify plugin to batch spotifysync lookups instead of making per-track API calls. It now:

• batches track metadata requests through /v1/tracks
• batches audio-features requests through /v1/audio-features
• deduplicates repeated Spotify track IDs within a run
• preserves the existing behavior that disables audio-features fetching after a Spotify 403

The previous implementation made one metadata request and one audio-features request per track, which was inefficient for larger libraries and increased the chance of hitting rate limits. Batching reduces request volume substantially while keeping the stored fields and user-facing behavior the same.

• Changelog. (Add an entry to docs/changelog.rst to the bottom of one of the lists near the top of the document.)
• Tests. (Very much encouraged but not strictly required.)

[Copilot]

Pull request overview

PR make Spotify spotifysync do fewer HTTP call. It batch track metadata and audio-features fetch, so big library not hit rate limit so fast.

Changes:

• Add batch fetch for /v1/tracks (50 ids per request) and /v1/audio-features (100 ids per request).
• Deduplicate repeated Spotify track IDs within one run of _fetch_info.
• Add tests for chunking, endpoint usage, dedupe, and 403-disable behavior; add changelog entry.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
beetsplug/spotify.py	Implement batch endpoints + ID chunking/dedupe and shared disable logic for audio features.
test/plugins/test_spotify.py	Add response mocks + assertions for batching/dedupe/403 behavior.
docs/changelog.rst	Add Unreleased changelog entry for Spotify batching change.

[codecov]

Codecov Report

❌ Patch coverage is 83.13253% with 14 lines in your changes missing coverage. Please review.
✅ Project coverage is 72.02%. Comparing base (20b0dd3) to head (e84ce41).
⚠️ Report is 30 commits behind head on master.

Files with missing lines	Patch %	Lines
beetsplug/spotify.py	82.05%	6 Missing and 8 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6485      +/-   ##
==========================================
- Coverage   72.05%   72.02%   -0.04%     
==========================================
  Files         159      159              
  Lines       20562    20622      +60     
  Branches     3260     3272      +12     
==========================================
+ Hits        14816    14852      +36     
- Misses       5055     5063       +8     
- Partials      691      707      +16     

Files with missing lines	Coverage Δ
beets/library/migrations.py	96.49% <100.00%> (-0.12%)	⬇️
beets/util/__init__.py	79.23% <100.00%> (+0.12%)	⬆️
beetsplug/spotify.py	62.59% <82.05%> (+11.99%)	⬆️

... and 2 files with indirect coverage changes

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[snejus]

A couple of comments

[snejus]

@arsaboo let me know once you've addressed all my comments (I see the edits to irrelevant docstrings are not yet fixed) and I will re-review!

[arsaboo]

@snejus, all comments are addressed, and the docstrings have been reverted (unless I missed something).

[snejus]

Apologies, I accidentally approved but I intended to select Request changes 😅

[arsaboo]

@snejus most of the formatting changes are made by doctstrfmt for the build to pass; there are no meaningful changes there. I reverted everything else.

[snejus]

docstrfmt should only be used to format rst files, not Python files (using poe format-docs).

The issue with your unrelated changes in the docstrings is that this obfuscates the original author of that docstring. I often git blame specific lines in the codebase to find the relevant context for that line or change.

Please undo the adjustments that I reviewed above.

[arsaboo]

@snejus cleaned up everything. Apologies for the back and forth.

[snejus]

Thanks!