sx-http: remove server-side fragment extraction — client handles sx-select

Server always returns full page. Client sx-select handles extraction.
No application logic in OCaml server.

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

hosts/ocaml/bin/sx_server.ml

@@ -2085,7 +2085,7 @@ let http_mode port =
   let n_workers = max 2 (Domain.recommended_domain_count ()) in
 
   (* Render queue: for cache misses that need full page render *)
-  let render_queue : (Unix.file_descr * string * bool) list ref = ref [] in
+  let render_queue : (Unix.file_descr * string) list ref = ref [] in
   let render_mutex = Mutex.create () in
   let render_cond = Condition.create () in
   let shutdown = ref false in
@@ -2106,64 +2106,14 @@ let http_mode port =
         w
       in
       match work with
-      | Some (fd, path, is_ajax) ->
+      | Some (fd, path) ->
         let response =
           try
             match http_render_page env path with
             | Some html ->
-              if is_ajax then begin
+              let resp = http_response html in
-                (* Extract #main-panel fragment for AJAX *)
+              Hashtbl.replace response_cache path resp;
-                let panel_start = try
+              resp
-                  let idx = ref 0 in
-                  let found = ref false in
-                  while not !found && !idx < String.length html - 20 do
-                    if String.sub html !idx 18 = "id=\"main-panel\"" then found := true
-                    else idx := !idx + 1
-                  done;
-                  if !found then begin
-                    let start = ref !idx in
-                    while !start > 0 && html.[!start] <> '<' do start := !start - 1 done;
-                    Some !start
-                  end else None
-                with _ -> None in
-                match panel_start with
-                | Some start ->
-                  (* Find the tag name (section, div, etc.) *)
-                  let tag_end = ref (start + 1) in
-                  while !tag_end < String.length html && html.[!tag_end] <> ' ' && html.[!tag_end] <> '>' do
-                    tag_end := !tag_end + 1
-                  done;
-                  let tag = String.sub html (start + 1) (!tag_end - start - 1) in
-                  (* Find matching close tag by counting depth *)
-                  let open_tag = "<" ^ tag in
-                  let close_tag = "</" ^ tag ^ ">" in
-                  let depth = ref 1 in
-                  let pos = ref (!tag_end) in
-                  let found_end = ref (String.length html) in
-                  while !depth > 0 && !pos < String.length html - String.length close_tag do
-                    if String.sub html !pos (String.length close_tag) = close_tag then begin
-                      depth := !depth - 1;
-                      if !depth = 0 then
-                        found_end := !pos + String.length close_tag
-                      else
-                        pos := !pos + 1
-                    end else if !pos + String.length open_tag < String.length html
-                              && String.sub html !pos (String.length open_tag) = open_tag
-                              && (html.[!pos + String.length open_tag] = ' '
-                                  || html.[!pos + String.length open_tag] = '>') then begin
-                      depth := !depth + 1;
-                      pos := !pos + 1
-                    end else
-                      pos := !pos + 1
-                  done;
-                  let fragment = String.sub html start (!found_end - start) in
-                  http_response ~content_type:"text/html; charset=utf-8" fragment
-                | None -> http_response html
-              end else begin
-                let resp = http_response html in
-                Hashtbl.replace response_cache path resp;
-                resp
-              end
             | None -> http_response ~status:404 "<h1>Not Found</h1>"
           with e ->
             Printf.eprintf "[render] Error for %s: %s\n%!" path (Printexc.to_string e);
@@ -2176,7 +2126,7 @@ let http_mode port =
 
   (* Fast path: handle a request from the main loop.
      Returns true if handled immediately (cached), false if queued. *)
-  let fast_handle fd data is_ajax =
+  let fast_handle fd data _is_ajax =
     match parse_http_request data with
     | None -> write_response fd (http_response ~status:400 "Bad Request"); true
     | Some (method_, raw_path) ->
@@ -2190,25 +2140,15 @@ let http_mode port =
         let is_sx = path = "/sx/" || path = "/sx"
           || (String.length path > 4 && String.sub path 0 4 = "/sx/") in
         if is_sx then begin
-          if not is_ajax then
+          (* Serve from cache (full page) — client handles sx-select extraction *)
-            (* Check cache — instant response *)
+          match Hashtbl.find_opt response_cache path with
-            match Hashtbl.find_opt response_cache path with
+          | Some cached -> write_response fd cached; true
-            | Some cached -> write_response fd cached; true
+          | None ->
-            | None ->
-              (* Queue for render worker *)
-              Mutex.lock render_mutex;
-              render_queue := !render_queue @ [(fd, path, false)];
-              Condition.signal render_cond;
-              Mutex.unlock render_mutex;
-              false
-          else begin
-            (* AJAX always renders fresh (no cache for fragments) *)
             Mutex.lock render_mutex;
-            render_queue := !render_queue @ [(fd, path, true)];
+            render_queue := !render_queue @ [(fd, path)];
             Condition.signal render_cond;
             Mutex.unlock render_mutex;
             false
-          end
         end else if String.length path > 8 && String.sub path 0 8 = "/static/" then begin
           write_response fd (serve_static_file static_dir path); true
         end else begin