Overhauled U8 archive handling

src/bin/rustwii/archive/theme.rs

@@ -0,0 +1,28 @@
+// archive/theme.rs from ruswtii (c) 2025 NinjaCheetah & Contributors
+// https://github.com/NinjaCheetah/rustwii
+//
+// Code for the theme building commands in the rustii CLI.
+
+use anyhow::{bail, Context, Result};
+use clap::Subcommand;
+use tempfile::tempdir;
+
+#[derive(Subcommand)]
+#[command(arg_required_else_help = true)]
+pub enum Commands {
+    /// Apply an MYM theme to the Wii Menu
+    ApplyMym {
+        /// The path to the source MYM file to apply
+        mym_path: String,
+        /// The path to the base Wii Menu asset archive (000000xx.app)
+        base_path: String,
+        /// The file to output the finished theme to (<filename>.csm)
+        output: String,
+    }
+}
+
+pub fn theme_apply_mym(mym_path: &str, base_path: &str, output: &str) -> Result<()> {
+    todo!();
+
+    Ok(())
+}