Major refactor

- CPU is now it's own module
- Memory object is now shared to support mapper chips
- ROM is now stored as `Arc<[u8]>` to support mapper chips

Cargo.toml

@@ -7,6 +7,7 @@ edition = "2024"
 bitfield = "0.19.3"
 # iced = { version = "0.14.0", features = ["debug", "canvas", "tokio", "lazy", "image", "advanced"] }
 iced = { path = "../iced", features = ["debug", "canvas", "tokio", "lazy", "image", "advanced"] }
+rfd = "0.17.2"
 # iced_graphics = { version = "0.14.0", features = ["geometry", "image"] }
 # iced_widget = { version = "0.13.4", features = ["canvas", "image"] }
 thiserror = "2.0.17"