feat: add Spotify playlist injection with ID-based configuration

.env.example

@@ -95,3 +95,28 @@ STORAGE_MODE=Permanent
 # Based on last access time (updated each time the file is streamed)
 # Cache location: /tmp/allstarr-cache (or $TMPDIR/allstarr-cache if TMPDIR is set)
 CACHE_DURATION_HOURS=1
+
+# ===== SPOTIFY PLAYLIST INJECTION (JELLYFIN ONLY) =====
+# REQUIRES: Jellyfin Spotify Import Plugin (https://github.com/Viperinius/jellyfin-plugin-spotify-import)
+# This feature intercepts Spotify Import plugin playlists (Release Radar, Discover Weekly) and fills them
+# with tracks auto-matched from external providers (SquidWTF, Deezer, Qobuz)
+# Uses JELLYFIN_URL and JELLYFIN_API_KEY configured above (no separate credentials needed)
+
+# Enable Spotify playlist injection (optional, default: false)
+SPOTIFY_IMPORT_ENABLED=false
+
+# Sync schedule: When does the Spotify Import plugin run?
+# Set these to match your plugin's sync schedule in Jellyfin
+# Example: If plugin runs daily at 4:15 PM, set HOUR=16 and MINUTE=15
+SPOTIFY_IMPORT_SYNC_START_HOUR=16
+SPOTIFY_IMPORT_SYNC_START_MINUTE=15
+
+# Sync window: How long to search for missing tracks files (in hours)
+# The fetcher will check every 5 minutes within this window
+# Example: If plugin runs at 4:15 PM and window is 2 hours, checks from 4:00 PM to 6:00 PM
+SPOTIFY_IMPORT_SYNC_WINDOW_HOURS=2
+
+# Playlist IDs to inject (comma-separated)
+# Get IDs from Jellyfin playlist URLs: https://jellyfin.example.com/web/#/details?id=PLAYLIST_ID
+# Example: SPOTIFY_IMPORT_PLAYLIST_IDS=4383a46d8bcac3be2ef9385053ea18df,ba50e26c867ec9d57ab2f7bf24cfd6b0
+SPOTIFY_IMPORT_PLAYLIST_IDS=