feat(sandbox): implement Linux sandbox helper binary

.github/workflows/test.yml

@@ -97,7 +97,7 @@ jobs:
         run: rustup component add llvm-tools-preview
 
       - name: Run tests with coverage
-        run: cargo llvm-cov --lcov --output-path lcov.info
+        run: cargo llvm-cov --workspace --lcov --output-path lcov.info
 
       - name: Upload coverage to Codecov
         uses: codecov/codecov-action@v5

Cargo.toml

@@ -1,3 +1,7 @@
+[workspace]
+members = [".", "crates/runok-linux-sandbox"]
+default-members = ["."]
+
 [package]
 name = "runok"
 version = "0.1.0"
@@ -18,6 +22,7 @@ shlex = "=1.3.0"
 thiserror = "=2.0.18"
 tree-sitter = "=0.25.10"
 tree-sitter-bash = "=0.25.1"
+which = "=8.0.0"
 
 [dev-dependencies]
 indoc = "=2.0.7"

crates/runok-linux-sandbox/Cargo.toml

@@ -0,0 +1,25 @@
+[package]
+name = "runok-linux-sandbox"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+anyhow = "=1.0.101"
+clap = { version = "=4.5.58", features = ["derive"] }
+landlock = "=0.4.3"
+libc = "=0.2.182"
+seccompiler = "=0.5.0"
+serde = { version = "=1.0.228", features = ["derive"] }
+serde_json = "=1.0.149"
+thiserror = "=2.0.18"
+
+[dev-dependencies]
+rstest = "=0.26.1"
+
+[lints.clippy]
+allow_attributes = "warn"
+allow_attributes_without_reason = "warn"
+disallowed_macros = "deny"
+expect_used = "deny"
+panic = "deny"
+unwrap_used = "deny"