IO registry: defio declares platform suspension points

Core SX has zero IO — platforms extend __io-registry via (defio name
:category :data/:code/:effect ...). The server web platform declares 44
operations in web/io.sx. batchable_helpers now derived from registry
(:batchable true) instead of hardcoded list. Startup validation warns if
bound IO ops lack registry entries. Browser gets empty registry, ready
for step 5 (IO suspension).

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

shared/static/wasm/sx/boot.sx

@@ -425,7 +425,6 @@
     ()
     (do
       (log-info (str "sx-browser " SX_VERSION))
-      (init-css-tracking)
       (process-page-scripts)
       (process-sx-scripts nil)
       (sx-hydrate-elements nil)
@@ -433,7 +432,6 @@
       (run-post-render-hooks)
       (flush-collected-styles)
       (set-timeout (fn () (process-elements nil)) 0)
-      (dom-listen (dom-window) "popstate" (fn (e) (handle-popstate 0)))
       (dom-set-attr
         (host-get (dom-document) "documentElement")
         "data-sx-ready"

shared/static/wasm/sx/engine.sx

@@ -117,7 +117,7 @@
   build-request-headers
   :effects (io)
   (fn
-    (el (loaded-components :as list) (css-hash :as string))
+    (el (loaded-components :as list))
     (let
       ((headers (dict "SX-Request" "true" "SX-Current-URL" (browser-location-href))))
       (let
@@ -126,7 +126,6 @@
       (let
         ((comp-hash (dom-get-attr (dom-query "script[data-components][data-hash]") "data-hash")))
         (when comp-hash (dict-set! headers "SX-Components-Hash" comp-hash)))
-      (when css-hash (dict-set! headers "SX-Css" css-hash))
       (let
         ((extra-h (dom-get-attr el "sx-headers")))
         (when
@@ -162,8 +161,6 @@
       (get-header "SX-Location")
       "replace-url"
       (get-header "SX-Replace-Url")
-      "css-hash"
-      (get-header "SX-Css-Hash")
       "trigger-swap"
       (get-header "SX-Trigger-After-Swap")
       "trigger-settle"

shared/static/wasm/sx/orchestration.sx

@@ -1,7 +1,5 @@
 (define _preload-cache (dict))
 
-(define _css-hash "")
-
 (define
   dispatch-trigger-events
   :effects (mutation io)
@@ -26,19 +24,6 @@
                   (dom-dispatch el trimmed (dict)))))
             (split header-val ",")))))))
 
-(define
-  init-css-tracking
-  :effects (mutation io)
-  (fn
-    ()
-    (let
-      ((meta (dom-query "meta[name=\"sx-css-classes\"]")))
-      (when
-        meta
-        (let
-          ((content (dom-get-attr meta "content")))
-          (when content (set! _css-hash content)))))))
-
 (define
   execute-request
   :effects (mutation io)
@@ -115,8 +100,7 @@
             (final-url (get body-info "url"))
             (body (get body-info "body"))
             (ct (get body-info "content-type"))
-            (headers
-              (build-request-headers el (loaded-component-names) _css-hash))
+            (headers (build-request-headers el (loaded-component-names)))
             (csrf (csrf-token)))
           (when
             extraParams
@@ -214,9 +198,6 @@
       (text :as string))
     (let
       ((resp-headers (process-response-headers get-header)))
-      (let
-        ((new-hash (get resp-headers "css-hash")))
-        (when new-hash (set! _css-hash new-hash)))
       (dispatch-trigger-events el (get resp-headers "trigger"))
       (process-cache-directives el resp-headers text)
       (cond
@@ -1144,8 +1125,7 @@
                               pathname
                               (build-request-headers
                                 target
-                                (loaded-component-names)
-                                _css-hash))
+                                (loaded-component-names)))
                             true)
                           (if
                             (get match "has-data")
@@ -1181,8 +1161,7 @@
                                                 pathname
                                                 (build-request-headers
                                                   target
-                                                  (loaded-component-names)
-                                                  _css-hash)
+                                                  (loaded-component-names))
                                                 0))
                                             (swap-rendered-content
                                               target
@@ -1240,8 +1219,7 @@
                                                     pathname
                                                     (build-request-headers
                                                       target
-                                                      (loaded-component-names)
-                                                      _css-hash)
+                                                      (loaded-component-names))
                                                     0))
                                                 (swap-rendered-content
                                                   target
@@ -1262,8 +1240,7 @@
                                                   pathname
                                                   (build-request-headers
                                                     target
-                                                    (loaded-component-names)
-                                                    _css-hash)
+                                                    (loaded-component-names))
                                                   0))
                                               (swap-rendered-content
                                                 target
@@ -1293,8 +1270,7 @@
                                           pathname
                                           (build-request-headers
                                             target
-                                            (loaded-component-names)
-                                            _css-hash)
+                                            (loaded-component-names))
                                           0))
                                       (swap-rendered-content
                                         target
@@ -1471,10 +1447,7 @@
                   info
                   (do-preload
                     (get info "url")
-                    (build-request-headers
-                      el
-                      (loaded-component-names)
-                      _css-hash)))))))))))
+                    (build-request-headers el (loaded-component-names))))))))))))
 
 (define
   do-preload
@@ -1592,8 +1565,4 @@
   :effects (mutation io)
   (fn
     ()
-    (do
-      (init-css-tracking)
-      (sx-process-scripts nil)
-      (sx-hydrate nil)
-      (process-elements nil))))
+    (do (sx-process-scripts nil) (sx-hydrate nil) (process-elements nil))))

shared/static/wasm/sx_browser.bc.wasm.js

@@ -1792,7 +1792,7 @@
             blake2_js_for_wasm_create: blake2_js_for_wasm_create};
    }
    (globalThis))
-({"link":[["runtime-0db9b496",0],["prelude-d7e4b000",0],["stdlib-23ce0836",[]],["sx-de8114db",[2]],["jsoo_runtime-f96b44a8",[2]],["js_of_ocaml-651f6707",[2,4]],["dune__exe__Sx_browser-9ecd0d53",[2,3,5]],["std_exit-10fb8830",[2]],["start-80fdb768",0]],"generated":(b=>{var
+({"link":[["runtime-0db9b496",0],["prelude-d7e4b000",0],["stdlib-23ce0836",[]],["sx-de8114db",[2]],["jsoo_runtime-f96b44a8",[2]],["js_of_ocaml-651f6707",[2,4]],["dune__exe__Sx_browser-2ca913af",[2,3,5]],["std_exit-10fb8830",[2]],["start-80fdb768",0]],"generated":(b=>{var
 c=b,a=b?.module?.export||b;return{"env":{"caml_ba_kind_of_typed_array":()=>{throw new
 Error("caml_ba_kind_of_typed_array not implemented")},"caml_exn_with_js_backtrace":()=>{throw new
 Error("caml_exn_with_js_backtrace not implemented")},"caml_int64_create_lo_mi_hi":()=>{throw new