feat: Allow authentication via SUBSONIC_SALT and SUBSONIC_TOKEN

Co-authored-by: aider (gemini/gemini-2.5-pro) <aider@aider.chat>

main.py

@@ -13,15 +13,23 @@ def main():
     """Get playlists from a Navidrome server using the Subsonic API."""
     navidrome_url = os.environ.get('NAVIDROME_URL')
     username = os.environ.get('NAVIDROME_USER')
-    password = os.environ.get('NAVIDROME_PASSWORD')
 
-    if not all([navidrome_url, username, password]):
-        logging.error("NAVIDROME_URL, NAVIDROME_USER, and NAVIDROME_PASSWORD environment variables must be set.")
+    if not all([navidrome_url, username]):
+        logging.error("NAVIDROME_URL and NAVIDROME_USER environment variables must be set.")
         return
 
-    # Subsonic API requires a salt and a token (md5(password + salt))
-    salt = ''.join(random.choice(string.ascii_lowercase + string.digits) for _ in range(10))
-    token = hashlib.md5((password + salt).encode('utf-8')).hexdigest()
+    salt = os.environ.get('SUBSONIC_SALT')
+    token = os.environ.get('SUBSONIC_TOKEN')
+
+    if not all([salt, token]):
+        password = os.environ.get('NAVIDROME_PASSWORD')
+        if not password:
+            logging.error("Either (SUBSONIC_SALT and SUBSONIC_TOKEN) or NAVIDROME_PASSWORD must be set.")
+            return
+
+        # Subsonic API requires a salt and a token (md5(password + salt))
+        salt = ''.join(random.choice(string.ascii_lowercase + string.digits) for _ in range(10))
+        token = hashlib.md5((password + salt).encode('utf-8')).hexdigest()
 
     params = {
         'u': username,