feat: implement worker lifecycle and sandbox

Cargo.toml

@@ -15,16 +15,25 @@ path = "src/lib.rs"
 name = "ghidr"
 path = "src/main.rs"
 
+[[bin]]
+name = "ghidr-fake-child"
+path = "tests/support/fake_child.rs"
+
 [dependencies]
 base64 = "0.22.1"
 clap = { version = "4.5.60", features = ["derive"] }
+getrandom = "=0.3.3"
+hex = "0.4.3"
+rustix = { version = "=1.0.8", features = ["process"] }
 schemars = { version = "=1.0.4", features = ["derive"] }
 serde = { version = "1.0.228", features = ["derive"] }
 serde_json = "1.0.149"
+sha2 = "0.10.9"
 thiserror = "2.0.18"
 
 [dev-dependencies]
 assert_cmd = "2.1.2"
+tempfile = "=3.21.0"
 
 [lints.rust]
 unsafe_code = "forbid"