Constant FIRST_CLASS_VALUE_KINDS 

pub const FIRST_CLASS_VALUE_KINDS: &[&str];

The CANONICAL set of value kinds that must be FIRST-CLASS as a function parameter AND return value on EVERY execution tier — the single source of truth SHARED across crates so the coverage locks cannot drift apart. The tests crate’s param_return_tier_coverage_lock asserts its PROBES name EXACTLY this set (executed on TW/VM/AOT-C/AOT-Rust, lowered on WASM), and this crate’s wasm_aot_lock::first_class_param_return_round_trips_on_wasm asserts it has an EXECUTABLE WASM program for every kind here. Adding a kind here makes BOTH locks RED until each covers it — anti-drift by construction, compiler-enforced (both crates reference this one const). Keep alphabetically grouped scalars → sequences → collections → aggregates for readability; order is not significant (compared as a set).