Workspace lints and disallow unwrap (#855)

Sets submodules to use workspace lints. Added denying unwrap as a
workspace level lint, which found a couple of cases where we could have
propagated errors. Also manually labeled ones that were fine by my eye.

codex-rs/core/src/codex.rs

@@ -1,3 +1,6 @@
+// Poisoned mutex should fail the program
+#![allow(clippy::unwrap_used)]
+
 use std::collections::HashMap;
 use std::collections::HashSet;
 use std::path::Path;