Cache-bust wasm scripts, fix orchestration.sx paren balance

- Add wasm_hash (MD5 of sx_browser.bc.js) to shell template
- Script tags: /wasm/sx_browser.bc.js?v={hash}, /wasm/sx-platform.js?v={hash}
- Pass wasm_hash through helpers.py and ocaml_bridge.py
- Fix missing close paren in bind-sse-swap (broke SX parsing)

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

shared/static/wasm/sx/orchestration.sx

@@ -300,7 +300,8 @@
                 (with-transition use-transition
                   (fn ()
                     (let ((swap-result (swap-dom-nodes target content swap-style)))
-                      (post-swap (or swap-result target))))))))))))
+                      (post-swap (or swap-result target)))))))))))))
+
 
 
 (define handle-html-response :effects [mutation io]
@@ -1083,7 +1084,7 @@
           (with-transition use-transition
             (fn ()
               (swap-html-string target trimmed swap-style)
-              (post-swap target))))))))
+              (post-swap target)))))))))
 
 
 ;; --------------------------------------------------------------------------

shared/sx/helpers.py

@@ -7,6 +7,7 @@ page elements (headers, search, etc.) from template context.
 from __future__ import annotations
 
 import hashlib
+import os
 from pathlib import Path
 from typing import Any
 
@@ -884,12 +885,14 @@ def _get_shell_static() -> dict[str, Any]:
         sx_css_classes=sx_css_classes,
         sx_js_hash=_script_hash("sx-browser.js"),
         body_js_hash=_script_hash("body.js"),
+        wasm_hash=_wasm_hash("sx_browser.bc.js"),
         asset_url=_ca.config.get("ASSET_URL", "/static"),
         head_scripts=_shell_cfg.get("head_scripts"),
         inline_css=_shell_cfg.get("inline_css"),
         inline_head_js=_shell_cfg.get("inline_head_js"),
         init_sx=_shell_cfg.get("init_sx"),
         body_scripts=_shell_cfg.get("body_scripts"),
+        use_wasm=os.environ.get("SX_USE_WASM") == "1",
     )
 
     t1 = time.monotonic()
@@ -1081,8 +1084,11 @@ def sx_page_streaming_parts(ctx: dict, page_html: str, *,
     # Tail: bootstrap suspense resolver + scripts + close
     tail = (
         _SX_STREAMING_BOOTSTRAP + '\n'
-        f'<script src="{asset_url}/scripts/sx-browser.js?v={sx_js_hash}"></script>\n'
+        + (f'<script src="{asset_url}/wasm/sx_browser.bc.wasm.js"></script>\n'
-        f'<script src="{asset_url}/scripts/body.js?v={body_js_hash}"></script>\n'
+           f'<script src="{asset_url}/wasm/sx-platform.js"></script>\n'
+           if os.environ.get("SX_USE_WASM") == "1" else
+           f'<script src="{asset_url}/scripts/sx-browser.js?v={sx_js_hash}"></script>\n')
+        + f'<script src="{asset_url}/scripts/body.js?v={body_js_hash}"></script>\n'
     )
 
     return shell, tail
@@ -1120,6 +1126,18 @@ def _script_hash(filename: str) -> str:
     return _SCRIPT_HASH_CACHE[filename]
 
 
+def _wasm_hash(filename: str) -> str:
+    """Compute MD5 hash of a static wasm file, cached for process lifetime."""
+    key = "wasm/" + filename
+    if key not in _SCRIPT_HASH_CACHE:
+        try:
+            data = (Path(__file__).resolve().parent.parent / "static" / "wasm" / filename).read_bytes()
+            _SCRIPT_HASH_CACHE[key] = hashlib.md5(data).hexdigest()[:8]
+        except OSError:
+            _SCRIPT_HASH_CACHE[key] = "dev"
+    return _SCRIPT_HASH_CACHE[key]
+
+
 def _get_csrf_token() -> str:
     """Get the CSRF token from the current request context."""
     try:

shared/sx/ocaml_bridge.py

@@ -190,7 +190,7 @@ class OcamlBridge:
         # Only inject small, safe values as kernel variables.
         # Large/complex blobs use placeholder tokens at render time.
         for key in ("component_hash", "sx_css_classes", "asset_url",
-                    "sx_js_hash", "body_js_hash"):
+                    "sx_js_hash", "body_js_hash", "wasm_hash"):
             val = static.get(key) or ""
             var = f"__shell-{key.replace('_', '-')}"
             defn = f'(define {var} "{_escape(str(val))}")'
@@ -268,7 +268,7 @@ class OcamlBridge:
                                 "sx_css", "inline_css", "inline_head_js"}
             placeholders = {}
             static_keys = {"component_hash", "sx_css_classes", "asset_url",
-                           "sx_js_hash", "body_js_hash",
+                           "sx_js_hash", "body_js_hash", "wasm_hash",
                            "head_scripts", "body_scripts"}
             # page_source is SX wire format that may contain \" escapes.
             # Send via binary blob protocol to avoid double-escaping

shared/sx/templates/shell.sx

@@ -17,8 +17,10 @@
                                (pages-sx :as string?) (page-sx :as string?)
                                (body-html :as string?)
                                (asset-url :as string) (sx-js-hash :as string) (body-js-hash :as string?)
+                               (wasm-hash :as string?)
                                (head-scripts :as list?) (inline-css :as string?) (inline-head-js :as string?)
-                               (init-sx :as string?) (body-scripts :as list?))
+                               (init-sx :as string?) (body-scripts :as list?)
+                               (use-wasm :as boolean?))
   (<>
     (raw! "<!doctype html>")
     (html :lang "en"
@@ -83,7 +85,12 @@ details.group{overflow:hidden}details.group>summary{list-style:none}details.grou
           (raw! (or pages-sx "")))
         (script :type "text/sx" :data-mount "#sx-root"
           (raw! (or page-sx "")))
-        (script :src (str asset-url "/scripts/sx-browser.js?v=" sx-js-hash))
+        (if use-wasm
+          (let ((wv (or wasm-hash "dev")))
+            (<>
+              (script :src (str asset-url "/wasm/sx_browser.bc.js?v=" wv))
+              (script :src (str asset-url "/wasm/sx-platform.js?v=" wv))))
+          (script :src (str asset-url "/scripts/sx-browser.js?v=" sx-js-hash)))
         ;; Body scripts — configurable per app
         ;; Pass a list (even empty) to override defaults; nil = use defaults
         (if (not (nil? body-scripts))

web/orchestration.sx

@@ -300,7 +300,8 @@
                 (with-transition use-transition
                   (fn ()
                     (let ((swap-result (swap-dom-nodes target content swap-style)))
-                      (post-swap (or swap-result target))))))))))))
+                      (post-swap (or swap-result target)))))))))))))
+
 
 
 (define handle-html-response :effects [mutation io]
@@ -1083,7 +1084,7 @@
           (with-transition use-transition
             (fn ()
               (swap-html-string target trimmed swap-style)
-              (post-swap target))))))))
+              (post-swap target)))))))))
 
 
 ;; --------------------------------------------------------------------------