refactor: enforce layered crates and Rust audit gates

.github/workflows/ci.yml

@@ -16,14 +16,13 @@ jobs:
       - uses: dtolnay/rust-toolchain@stable
         with:
           components: rustfmt, clippy
+      - uses: dtolnay/rust-toolchain@nightly
       - uses: Swatinem/rust-cache@v2
+      - run: cargo +nightly -Zscript scripts/audit-rules.rs --self-test
+      - run: cargo +nightly -Zscript scripts/audit-rules.rs
       - run: cargo fmt --all -- --check
       - run: cargo clippy --workspace --all-targets -- -D warnings
       - run: cargo test --workspace --all-targets
-      - name: enforce flat crate source
-        run: test -z "$(find crates/*/src -mindepth 2 -type d -print)"
-      - name: forbid unsafe and no_std markers
-        run: "! rg '\\bunsafe\\b|libc|no_std' crates Cargo.toml -g '*.rs' -g '*.toml'"
       - name: optional plot feature
         run: cargo check -p chassis-tune --features plot --all-targets
       - name: deterministic tuning smoke
@@ -42,7 +41,7 @@ jobs:
           sudo modprobe vcan
           sudo ip link add dev vcan0 type vcan
           sudo ip link set up vcan0
-      - run: cargo test -p socketcan@0.1.0 --test vcan -- --ignored --test-threads 1
+      - run: cargo test -p integration-tests --test socketcan_vcan -- --ignored --test-threads 1
 
   cross-check:
     runs-on: ubuntu-latest