Rename playlist /tracks endpoints to /items

[wardbox]

Context

Part of the Spotify Feb 2026 API changes (#70). Playlist track management endpoints are renamed:

• GET/POST/DELETE/PUT /playlists/{id}/tracks → /playlists/{id}/items
• Request parameter tracks → items

Files affected (5)

• Spotishell/Public/Playlists/Get-PlaylistItems.ps1
• Spotishell/Public/Playlists/Add-PlaylistItem.ps1
• Spotishell/Public/Playlists/Remove-PlaylistItems.ps1
• Spotishell/Public/Playlists/Edit-PlaylistOrder.ps1
• Spotishell/Public/Playlists/Set-PlaylistItems.ps1

Notes

• Straightforward find-and-replace: /tracks → /items in URLs
• Also check for tracks parameter in request bodies that should become items
• Response field tracks → items in playlist objects may affect Get-Playlist.ps1 response handling

[wardbox]

Addressed in two PRs:

• Rename playlist /tracks endpoints to /items #77 — Endpoint URL rename (/tracks → /items) + body key rename (merged)
• Rename Remove-PlaylistItems $Track param to $Item #79 — $Track parameter renamed to $Item with [Alias('Track')] for backward compat