support metamodule, remove built-in overlayfs mount

Co-authored-by: weishu <twsxtd@gmail.com>
Co-authored-by: YuKongA <70465933+YuKongA@users.noreply.github.com>
Co-authored-by: Ylarod <me@ylarod.cn>

userspace/meta-overlayfs/Cargo.toml

@@ -0,0 +1,24 @@
+[package]
+name = "meta-overlayfs"
+version = "1.0.0"
+edition = "2024"
+authors = ["KernelSU Developers"]
+description = "An implementation of a metamodule using OverlayFS for KernelSU"
+license = "GPL-3.0"
+
+[dependencies]
+anyhow = "1"
+log = "0.4"
+env_logger = { version = "0.11", default-features = false }
+hole-punch = { git = "https://github.com/tiann/hole-punch" }
+
+[target.'cfg(any(target_os = "linux", target_os = "android"))'.dependencies]
+rustix = { git = "https://github.com/Kernel-SU/rustix.git", rev = "4a53fbc7cb7a07cabe87125cc21dbc27db316259", features = ["all-apis"] }
+procfs = "0.17"
+
+[profile.release]
+strip = true
+opt-level = "z"       # Minimize binary size
+lto = true            # Link-time optimization
+codegen-units = 1     # Maximum optimization
+panic = "abort"       # Reduce binary size