docs: polish rtorrent URL path documentation to exact specifications

- Update .env.sample RTORRENT_INSTANCES section with exact comment format
- Update README.md rTorrent table row with specific endpoint note
- Add explicit "No path is automatically appended" statement in README
- RTorrentClient.js already uses exact URL from config (no changes needed)

README.md

@@ -205,7 +205,7 @@ sofarr uses a **Pluggable Download Client Architecture (PDCA)** that provides a
 | SABnzbd | REST API | API Key | Usenet downloads |
 | qBittorrent | Sync API | Username/Password | BitTorrent with incremental updates |
 | Transmission | JSON-RPC | Username/Password | BitTorrent with session management |
-| rTorrent | XML-RPC | HTTP Basic Auth | BitTorrent, requires full endpoint path |
+| rTorrent | XML-RPC | HTTP Basic Auth | BitTorrent, requires the full RPC endpoint in the url field (e.g. /RPC2 or /xmlrpc for whatbox.ca). No path is automatically appended. |
 
 ### Service Instances (JSON Array Format)
 
@@ -223,6 +223,7 @@ TRANSMISSION_INSTANCES=[{"name":"main","url":"http://transmission:9091/transmiss
 
 # rTorrent Instances (uses username/password, URL must include full RPC endpoint)
 # Standard installs use /RPC2. Some providers like whatbox.ca use /xmlrpc.
+# No path is automatically appended - always include the full RPC endpoint.
 RTORRENT_INSTANCES=[{"name":"main","url":"http://rtorrent:8080/RPC2","username":"rtorrent","password":"rtorrent"}]
 
 # For whatbox.ca (example):