floats iter 3.3: install Float constants nan/inf/neg_inf + io/print_float effect op

crates/ailang-codegen/src/synth.rs

@@ -177,6 +177,11 @@ pub(crate) fn builtin_ail_type(name: &str) -> Option<Type> {
             param_modes: vec![],
             ret_mode: ParamMode::Implicit,
         },
+        // Iter 22-floats.3: Float bit-pattern constants. Bare values,
+        // not fns — referenced via `Term::Var`. Mirrors the
+        // typechecker's `builtins::install`. Codegen emits LLVM hex-
+        // float literals at the use site in iter 4.
+        "nan" | "inf" | "neg_inf" => Type::float(),
         _ => return None,
     })
 }
@@ -185,7 +190,7 @@ pub(crate) fn builtin_ail_type(name: &str) -> Option<Type> {
 /// param signature is irrelevant here since we only consume the ret.
 pub(crate) fn builtin_effect_op_ret(op: &str) -> Option<Type> {
     Some(match op {
-        "io/print_int" | "io/print_bool" | "io/print_str" => Type::unit(),
+        "io/print_int" | "io/print_bool" | "io/print_str" | "io/print_float" => Type::unit(),
         _ => return None,
     })
 }