feat(readarr): fetch Readarr updates and expose them on the CLI

Adds ReadarrEvent::GetUpdates backed by get_readarr_updates, rendering the
update history into the Readarr updates view, and surfaces it as
'readarr list updates'.

Covers the case where an update record omits the changes key, which the
live instance returns for its most recent release.

src/cli/readarr/list_command_handler.rs

@@ -19,6 +19,8 @@ mod list_command_handler_tests;
 pub enum ReadarrListCommand {
   #[command(about = "List disk space details for all provisioned root folders in Readarr")]
   DiskSpace,
+  #[command(about = "List all Readarr updates")]
+  Updates,
 }
 
 impl From<ReadarrListCommand> for Command {
@@ -55,6 +57,13 @@ impl<'a, 'b> CliCommandHandler<'a, 'b, ReadarrListCommand> for ReadarrListComman
           .await?;
         serde_json::to_string_pretty(&resp)?
       }
+      ReadarrListCommand::Updates => {
+        let resp = self
+          .network
+          .handle_network_event(ReadarrEvent::GetUpdates.into())
+          .await?;
+        serde_json::to_string_pretty(&resp)?
+      }
     };
 
     Ok(result)