eval ir generation: adjust autohook-allowance to be a stack, and correctly disable it for all sub-evaluations when using a raw lens, such that autohooks do not apply for evaluation of the parameter (e.g. raw(foo) -> foo, without allowing mapping of foo to something else)

src/eval/eval_ir.h

@@ -154,6 +154,7 @@ struct E_IRState
   
   // rjf: overridden irtree
   E_IRTreeAndType *overridden_irtree;
+  B32 disallow_autohooks;
   
   // rjf: caches
   E_UsedExprMap *used_expr_map;