Show read-only markers in CLI output (Option A)

Changed DeviceState Display trait to use to_string_with_readonly_info()
instead of to_string_with_padding().

This allows CLI users to see which features are hardware-limited before
attempting to use them, providing helpful context and reducing confusion
about why certain commands might not work.

The tray application continues to use to_string_with_padding() since
it's display-only and doesn't allow user interaction.

Implements Option A as discussed in PR #14

src/devices/mod.rs

@@ -84,7 +84,7 @@ pub struct DeviceState {
 
 impl Display for DeviceState {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{}", self.to_string_with_padding(25))
+        write!(f, "{}", self.to_string_with_readonly_info(25))
     }
 }