Fix primitive? lookup + replace coercion; remove debug output

primitive? in make_server_env was checking env bindings only (NativeFn),
missing all 132 primitives in the Sx_primitives hashtable. Now checks
both primitives table and env. get-primitive similarly fixed.

replace primitive now coerces SxExpr/Thunk/RawHTML/etc to strings instead
of crashing with "replace: 3 string args" — fixes aser JIT DISABLED.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

hosts/ocaml/bin/sx_server.ml

@@ -593,14 +593,17 @@ let make_server_env () =
   bind "primitive?" (fun args ->
     match args with
     | [String name] ->
-      (* Check if name is bound in the env as a NativeFn *)
-      (try match env_get env name with NativeFn _ -> Bool true | _ -> Bool false
-       with _ -> Bool false)
+      (* Check both the primitives table and the env *)
+      Bool (Sx_primitives.is_primitive name ||
+            (try (match env_get env name with NativeFn _ -> true | _ -> false)
+             with _ -> false))
     | _ -> Bool false);
   bind "get-primitive" (fun args ->
     match args with
     | [String name] ->
-      (try env_get env name with _ -> Nil)
+      (* Check primitives table first, then env *)
+      (try Sx_primitives.get_primitive name
+       with _ -> try env_get env name with _ -> Nil)
     | _ -> Nil);
 
   (* Character classification — platform primitives for spec/parser.sx *)