feat: add move_tracks script for playlist track migration

[jmlrt]

Summary

Add hacks/move_tracks.py script to move tracks between Spotify playlists with flexible sorting. This is a one-off hack designed to be migrated into the CLI later.

Changes

• hacks/move_tracks.py (157 lines)

  • parse_playlist_identifier() — Extract 22-char ID from Spotify URLs
  • resolve_identifier() — Resolve URLs/names to playlist IDs using existing utilities
  • move_tracks() — Core logic: sort by artist/album, add tracks, remove from source
  • Supports dry-run mode and verbose logging

• tests/test_move_tracks.py (475 lines)

  • 18 unit tests covering URL parsing, playlist resolution, sorting, dry-run behavior, edge cases
  • 100% code coverage for both files

Key Features

• Playlist identification: Accepts Spotify URLs, 22-char IDs, or playlist names
• Sorting: Alphabetically by first artist name, then album name (case-insensitive)
• Dry-run mode: Preview changes without modifying Spotify or DB
• Safe operations: Pre-flight + post-operation updates ensure DB consistency
• Edge case handling: Gracefully handles missing artist/album metadata
• CLI-ready: Function signature designed for future migration to main CLI

Testing

• ✅ 18/18 new tests pass
• ✅ All 333 existing tests still pass (no regressions)
• ✅ Code style passes ruff checks
• ✅ No secrets or artifacts in staged files

Example Usage

# Dry-run: see what would be moved
uv run python hacks/move_tracks.py \
  -s "https://open.spotify.com/playlist/4V8O33t0hSCnK4ABozG6xc?si=..." \
  -d "08h4c8EqOH2F8TsWXLIczV" \
  -n 22 --dry-run

# Live: move 22 tracks (sorted by artist, then album)
uv run python hacks/move_tracks.py \
  -s "Source Playlist Name" \
  -d "Destination Playlist ID" \
  -n 22

Future Migration

When ready to integrate into the CLI:

1. Move move_tracks() function to spotfm/spotify/misc.py
2. Add "move-tracks" command to spotfm/cli.py spotify command choices
3. Add CLI flags: --source-playlist, --dest-playlist, --count, --dry-run
4. Delete or repurpose hacks/move_tracks.py

The function signature is already CLI-compatible.