Dereference workspace lints for nix-cargo-integration compatibility

Replace `[lints] workspace = true` with explicit lint configuration in
each crate's Cargo.toml. This allows nix-cargo-integration to build
individual crates in isolation, as it cannot resolve workspace-level
lint configuration when building crates independently.

nix-bindings-expr/Cargo.toml

@@ -17,5 +17,11 @@ ctor = "0.2"
 tempfile = "3.10"
 cstr = "0.2"
 
-[lints]
-workspace = true
+[lints.rust]
+warnings = "deny"
+dead-code = "allow"
+
+[lints.clippy]
+type-complexity = "allow"
+# We're still trying to make Nix more thread-safe, want forward-compat
+arc-with-non-send-sync = "allow"