Fix signal-add-sub! losing subscribers after remove, fix build pipeline

signal-add-sub! used (append! subscribers f) which returns a new list
for immutable List but discards the result — after signal-remove-sub!
replaces the subscribers list via dict-set!, re-adding subscribers
silently fails. Counter island only worked once (0→1 then stuck).

Fix: use (dict-set! s "subscribers" (append ...)) to explicitly update
the dict field, matching signal-remove-sub!'s pattern.

Build pipeline fixes:
- sx-build-all.sh now bundles spec→dist and recompiles .sxbc bytecode
- compile-modules.js syncs .sx source files alongside .sxbc to wasm/sx/
- Per-file cache busting: wasm, platform JS, and sxbc each get own hash
- bundle.sh adds cssx.sx to dist

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

hosts/ocaml/bin/sx_server.ml

@@ -1597,6 +1597,8 @@ let http_render_page env path headers =
             Keyword "sx-css-classes"; get_shell "sx-css-classes";
             Keyword "asset-url"; get_shell "asset-url";
             Keyword "wasm-hash"; get_shell "wasm-hash";
+            Keyword "platform-hash"; get_shell "platform-hash";
+            Keyword "sxbc-hash"; get_shell "sxbc-hash";
             Keyword "inline-css"; get_shell "inline-css";
             Keyword "inline-head-js"; get_shell "inline-head-js";
             Keyword "init-sx"; get_shell "init-sx";
@@ -1678,6 +1680,20 @@ let file_hash path =
     String.sub (Digest.string (In_channel.with_open_bin path In_channel.input_all) |> Digest.to_hex) 0 12
   else ""
 
+let sxbc_combined_hash dir =
+  let sxbc_dir = dir ^ "/sx" in
+  if Sys.file_exists sxbc_dir && Sys.is_directory sxbc_dir then begin
+    let files = Array.to_list (Sys.readdir sxbc_dir) in
+    let sxbc_files = List.filter (fun f -> Filename.check_suffix f ".sxbc") files in
+    let sorted = List.sort String.compare sxbc_files in
+    let buf = Buffer.create 65536 in
+    List.iter (fun f ->
+      let path = sxbc_dir ^ "/" ^ f in
+      Buffer.add_string buf (In_channel.with_open_bin path In_channel.input_all)
+    ) sorted;
+    String.sub (Digest.string (Buffer.contents buf) |> Digest.to_hex) 0 12
+  end else ""
+
 let read_css_file path =
   if Sys.file_exists path then
     In_channel.with_open_text path In_channel.input_all
@@ -1726,8 +1742,10 @@ let http_inject_shell_statics env static_dir sx_sxc =
      literals, preventing the HTML parser from matching </script>. *)
   let component_defs = raw_defs in
   let component_hash = Digest.string component_defs |> Digest.to_hex in
-  (* Compute file hashes for cache busting *)
+  (* Compute per-file hashes for cache busting *)
   let wasm_hash = file_hash (static_dir ^ "/wasm/sx_browser.bc.wasm.js") in
+  let platform_hash = file_hash (static_dir ^ "/wasm/sx-platform-2.js") in
+  let sxbc_hash = sxbc_combined_hash (static_dir ^ "/wasm") in
   (* Read CSS for inline injection *)
   let tw_css = read_css_file (static_dir ^ "/styles/tw.css") in
   let basics_css = read_css_file (static_dir ^ "/styles/basics.css") in
@@ -1781,6 +1799,8 @@ let http_inject_shell_statics env static_dir sx_sxc =
   ignore (env_bind env "__shell-sx-css-classes" (String ""));
   ignore (env_bind env "__shell-asset-url" (String "/static"));
   ignore (env_bind env "__shell-wasm-hash" (String wasm_hash));
+  ignore (env_bind env "__shell-platform-hash" (String platform_hash));
+  ignore (env_bind env "__shell-sxbc-hash" (String sxbc_hash));
   ignore (env_bind env "__shell-inline-css" Nil);
   ignore (env_bind env "__shell-inline-head-js" Nil);
   (* init-sx: trigger client-side render when sx-root is empty (SSR failed).
@@ -1793,8 +1813,8 @@ let http_inject_shell_statics env static_dir sx_sxc =
        SX.renderPage(); \
      } \
      });"));
-  Printf.eprintf "[sx-http] Shell statics: defs=%d hash=%s css=%d wasm=%s\n%!"
-    (String.length component_defs) component_hash (String.length sx_css) wasm_hash
+  Printf.eprintf "[sx-http] Shell statics: defs=%d hash=%s css=%d wasm=%s platform=%s sxbc=%s\n%!"
+    (String.length component_defs) component_hash (String.length sx_css) wasm_hash platform_hash sxbc_hash
 
 let http_setup_declarative_stubs env =
   (* Stub declarative forms that are metadata-only — no-ops at render time. *)

hosts/ocaml/browser/bundle.sh

@@ -65,6 +65,9 @@ cp "$ROOT/web/engine.sx"        "$DIST/sx/"
 cp "$ROOT/web/orchestration.sx" "$DIST/sx/"
 cp "$ROOT/web/boot.sx"          "$DIST/sx/"
 
+# 9. CSSX (stylesheet language)
+cp "$ROOT/sx/sx/cssx.sx"        "$DIST/sx/"
+
 # Summary
 WASM_SIZE=$(du -sh "$DIST/sx_browser.bc.wasm.assets" | cut -f1)
 JS_SIZE=$(du -sh "$DIST/sx_browser.bc.js" | cut -f1)

hosts/ocaml/browser/compile-modules.js

@@ -185,6 +185,7 @@ const staticSxDir = path.resolve(__dirname, '..', '..', '..', 'shared', 'static'
 if (fs.existsSync(staticSxDir)) {
   let copied = 0;
   for (const file of FILES) {
+    // Copy bytecode
     for (const ext of ['.sxbc', '.sxbc.json']) {
       const src = path.join(sxDir, file.replace(/\.sx$/, ext));
       const dst = path.join(staticSxDir, file.replace(/\.sx$/, ext));
@@ -193,6 +194,13 @@ if (fs.existsSync(staticSxDir)) {
         copied++;
       }
     }
+    // Also sync .sx source files (fallback when .sxbc missing)
+    const sxSrc = path.join(sxDir, file);
+    const sxDst = path.join(staticSxDir, file);
+    if (fs.existsSync(sxSrc) && !fs.lstatSync(sxSrc).isSymbolicLink()) {
+      fs.copyFileSync(sxSrc, sxDst);
+      copied++;
+    }
   }
   console.log('Copied', copied, 'files to', staticSxDir);
 }

hosts/ocaml/browser/sx-platform.js

@@ -180,8 +180,12 @@
 
   var _baseUrl = "";
 
-  // Detect base URL from current script
+  // Detect base URL and cache-bust params from current script tag.
+  // _cacheBust comes from the script's own ?v= query string (used for .sx source fallback).
+  // _sxbcCacheBust comes from data-sxbc-hash attribute — a separate content hash
+  // covering all .sxbc files so each file gets its own correct cache buster.
   var _cacheBust = "";
+  var _sxbcCacheBust = "";
   (function() {
     if (typeof document !== "undefined") {
       var scripts = document.getElementsByTagName("script");
@@ -191,6 +195,8 @@
           _baseUrl = src.substring(0, src.lastIndexOf("/") + 1);
           var qi = src.indexOf("?");
           if (qi !== -1) _cacheBust = src.substring(qi);
+          var sxbcHash = scripts[i].getAttribute("data-sxbc-hash");
+          if (sxbcHash) _sxbcCacheBust = "?v=" + sxbcHash;
           break;
         }
       }
@@ -233,7 +239,7 @@
    */
   function loadBytecodeFile(path) {
     var bcPath = path.replace(/\.sx$/, '.sxbc.json');
-    var url = _baseUrl + bcPath + _cacheBust;
+    var url = _baseUrl + bcPath + _sxbcCacheBust;
     try {
       var xhr = new XMLHttpRequest();
       xhr.open("GET", url, false);