Update status field to be optional

The status field in MagbotConfig is now an Option<MagbotStatus> instead
of a direct MagbotStatus value, allowing it to be None when not
configured.
```

magbot-rs/src/config.rs

@@ -26,6 +26,7 @@ pub struct MagbotConfig {
     pub username: String,
     pub password: String,
     pub room_id: String,
+    pub status: Option<MagbotStatus>,
 }
 impl MagbotConfig {
     pub fn from_str(input: &str) -> anyhow::Result<Self> {