feat(userspace): shell runs programs (ls, cat) via spawn w/ terminal+storage+args page; ext4 holes read as zeros; storage re-attach same buffer

crates/apps/cat/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "cat"
+version = "0.1.0"
+edition = "2024"
+
+[[bin]]
+name = "cat"
+test = false
+bench = false
+
+[dependencies]
+types = { workspace = true }
+libkos = { workspace = true }