JIT live globals fix + non-blocking server + honest nav tests

JIT: use live globals table directly (no Hashtbl.copy snapshot).
Fixes CSSX "Not callable: nil" — 0 JIT errors on navigation.

Non-blocking server: accept loop serves cached/static instantly,
render workers handle cache misses. TCP backlog 1024, socket timeouts.

Navigation tests (8 tests):
- 6 pass: layout, content update, raw SX check, header survival,
  back button layout, full width
- 1 fail: back button content doesn't update (AJAX fragment issue)
- 1 fail: was JIT errors, now passes after fix

AJAX fragment extraction: code exists but not working for popstate
fetches. Needs investigation — SX-Request header detection or
fragment extraction logic.

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

hosts/ocaml/bin/sx_server.ml

@@ -400,11 +400,15 @@ let setup_evaluator_bridge env =
     match args with
     | [thunk; handler] ->
       (try Sx_ref.cek_call thunk Nil
-       with Eval_error msg -> Sx_ref.cek_call handler (List [String msg]))
+       with Eval_error msg ->
+         let enhanced = Sx_ref.enhance_error_with_trace msg in
+         Sx_ref.cek_call handler (List [String enhanced]))
     | [thunk] ->
       (try let r = Sx_ref.cek_call thunk Nil in
         List [Symbol "ok"; r]
-       with Eval_error msg -> List [Symbol "error"; String msg])
+       with Eval_error msg ->
+         let enhanced = Sx_ref.enhance_error_with_trace msg in
+         List [Symbol "error"; String enhanced])
     | _ -> Nil);
   bind "cek-call" (fun args ->
     match args with
@@ -617,7 +621,9 @@ let setup_strict_mode env =
   bind "set-strict!" (fun args -> match args with [v] -> Sx_ref._strict_ref := v; ignore (env_set env "*strict*" v); Nil | _ -> raise (Eval_error "set-strict!: expected 1 arg"));
   bind "set-prim-param-types!" (fun args -> match args with [v] -> Sx_ref._prim_param_types_ref := v; ignore (env_set env "*prim-param-types*" v); Nil | _ -> raise (Eval_error "set-prim-param-types!: expected 1 arg"));
   bind "component-param-types" (fun _args -> Nil);
-  bind "component-set-param-types!" (fun _args -> Nil)
+  bind "component-set-param-types!" (fun _args -> Nil);
+  bind "component-file" (fun args -> match args with [v] -> component_file v | _ -> Nil);
+  bind "component-set-file!" (fun args -> match args with [v; f] -> component_set_file v f | _ -> Nil)
 
 (* ---- IO helpers routed to Python bridge ---- *)
 let setup_io_bridges env =
@@ -678,14 +684,14 @@ let make_server_env () =
 (* ====================================================================== *)
 
 (** Render an SX expression to HTML using the SX adapter (adapter-html.sx).
-    Falls back to Sx_render.render_to_html if the SX adapter isn't loaded. *)
+    Falls back to Sx_render.sx_render_to_html if the SX adapter isn't loaded. *)
 let sx_render_to_html expr env =
   if env_has env "render-to-html" then
     let fn = env_get env "render-to-html" in
     let result = Sx_ref.cek_call fn (List [expr; Env env]) in
     match result with String s -> s | _ -> Sx_runtime.value_to_str result
   else
-    Sx_render.render_to_html expr env
+    Sx_render.sx_render_to_html env expr env
 
 
 (* ====================================================================== *)
@@ -768,6 +774,8 @@ let rec dispatch env cmd =
   | List [Symbol "load"; String path] ->
     (try
       let exprs = Sx_parser.parse_file path in
+      let prev_file = if Sx_types.env_has env "*current-file*" then Some (Sx_types.env_get env "*current-file*") else None in
+      ignore (Sx_types.env_bind env "*current-file*" (String path));
       let count = ref 0 in
       List.iter (fun expr ->
         ignore (Sx_ref.eval_expr expr (Env env));
@@ -776,6 +784,9 @@ let rec dispatch env cmd =
       (* Rebind host extension points after .sx load — evaluator.sx
          defines *custom-special-forms* which shadows the native dict *)
       rebind_host_extensions env;
+      (match prev_file with
+       | Some v -> ignore (Sx_types.env_bind env "*current-file*" v)
+       | None -> ());
       send_ok_value (Number (float_of_int !count))
     with
     | Eval_error msg -> send_error msg
@@ -831,7 +842,7 @@ let rec dispatch env cmd =
       in
       send_ok_raw (raw_serialize result)
     with
-    | Eval_error msg -> send_error msg
+    | Eval_error msg -> send_error (Sx_ref.enhance_error_with_trace msg)
     | exn -> send_error (Printexc.to_string exn))
 
   | List [Symbol "vm-reset-fn"; String name] ->
@@ -1538,7 +1549,7 @@ let http_render_page env path =
           | _ -> Sx_runtime.value_to_str result
         end else
           (* Fallback: native renderer *)
-          Sx_render.render_to_html_streaming body_expr env
+          Sx_render.sx_render_to_html env body_expr env
       with e ->
         Printf.eprintf "[http-ssr] failed for %s: %s\n%!" path (Printexc.to_string e); ""
     in
@@ -1579,7 +1590,7 @@ let http_render_page env path =
         | String s | RawHTML s -> s
         | _ -> Sx_runtime.value_to_str result
       end else
-        Sx_render.render_to_html_streaming shell_call env
+        Sx_render.sx_render_to_html env shell_call env
     in
     let t4 = Unix.gettimeofday () in
     Printf.eprintf "[sx-http] %s route=%.3fs aser=%.3fs ssr=%.3fs shell=%.3fs total=%.3fs html=%d\n%!"
@@ -2228,6 +2239,7 @@ let http_mode port =
       if n > 0 then begin
         let data = Bytes.sub_string buf 0 n in
         let is_ajax = is_sx_request data in
+        if is_ajax then Printf.eprintf "[sx-http] AJAX request detected\n%!";
         let handled =
           try fast_handle client data is_ajax
           with e ->