fix: playlist truncation overflow and align logging across plugins

- Fix format_playlist truncation: +4 → +5 to account for ", ..." suffix
- Add API error logging to all Sopel command handlers (matching Limnoria)
- Add long-track truncation test case

Made-with: Cursor

plugins/limnoria/NtrPlaylist/plugin.py

@@ -94,7 +94,7 @@ def format_playlist(data: dict) -> str:
     for t in tracks:
         entry = f"{t.get('title', '')} by {t.get('artist', '')}"
         sep = ", " if parts else ""
-        if length + len(sep) + len(entry) + 4 > _MAX_IRC_LINE:  # +4 for " ..."
+        if length + len(sep) + len(entry) + 5 > _MAX_IRC_LINE:  # +5 for ", ..."
             parts.append("...")
             break
         parts.append(entry)