Remove old CSSX system — ~tw is the sole CSS engine

Phase 1 Step 1 of the architecture roadmap. The old cssx.sx
(cssx-resolve, cssx-process-token, cssx-template, old tw function)
is superseded by the ~tw component system in tw.sx.

- Delete shared/sx/templates/cssx.sx
- Remove cssx.sx from all load lists (sx_server.ml, run_tests.ml,
  mcp_tree.ml, compile-modules.js, bundle.sh, sx-build-all.sh)
- Replace (tw "tokens") inline style calls with (~tw :tokens "tokens")
  in layouts.sx and not-found.sx
- Remove _css-hash / init-css-tracking / SX-Css header plumbing
  (dead code — ~tw/flush + flush-collected-styles handle CSS now)
- Remove sx-css-classes param and meta tag from shell template
- Update stale data-cssx references to data-sx-css in tests

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

sx/sx/layouts.sx

@@ -87,8 +87,7 @@
             :sx-select "#sx-content"
             :sx-swap "innerHTML"
             :sx-push-url "true"
-            (~tw :tokens "text-right min-w-0 truncate")
-            :style (tw "text-stone-500 text-sm")
+            (~tw :tokens "text-right min-w-0 truncate text-stone-500 text-sm")
             (str "← " (get prev-node "label")))
           (a
             :href (get node "href")
@@ -97,11 +96,13 @@
             :sx-select "#sx-content"
             :sx-swap "innerHTML"
             :sx-push-url "true"
-            (~tw :tokens "text-center min-w-0 truncate px-1")
-            :style (if
-              is-leaf
-              (tw "text-violet-700 text-2xl font-bold")
-              (tw "text-violet-700 text-lg font-semibold"))
+            (~tw
+              :tokens (str
+                "text-center min-w-0 truncate px-1 "
+                (if
+                  is-leaf
+                  "text-violet-700 text-2xl font-bold"
+                  "text-violet-700 text-lg font-semibold")))
             (get node "label"))
           (a
             :href (get next-node "href")
@@ -110,8 +111,7 @@
             :sx-select "#sx-content"
             :sx-swap "innerHTML"
             :sx-push-url "true"
-            (~tw :tokens "text-left min-w-0 truncate")
-            :style (tw "text-stone-500 text-sm")
+            (~tw :tokens "text-left min-w-0 truncate text-stone-500 text-sm")
             (str (get next-node "label") " →")))))))
 
 (defcomp
@@ -132,8 +132,8 @@
             :sx-select "#sx-content"
             :sx-swap "innerHTML"
             :sx-push-url "true"
-            (~tw :tokens "px-3 py-1.5 rounded border transition-colors")
-            :style (tw "text-violet-700 text-sm border-violet-200")
+            (~tw
+              :tokens "px-3 py-1.5 rounded border transition-colors text-violet-700 text-sm border-violet-200")
             (get item "label")))
         items))))
 

sx/sx/not-found.sx

@@ -3,11 +3,11 @@
   (&key (path :as string?))
   (div
     (~tw :tokens "max-w-3xl mx-auto px-4 py-12 text-center")
-    (h1 :style (tw "text-stone-800 text-3xl font-bold") "404")
-    (p (~tw :tokens "mt-4") :style (tw "text-stone-500 text-lg") "Page not found")
+    (h1 (~tw :tokens "text-stone-800 text-3xl font-bold") "404")
+    (p (~tw :tokens "mt-4 text-stone-500 text-lg") "Page not found")
     (when
       path
-      (p (~tw :tokens "mt-2") :style (tw "text-stone-400 text-sm font-mono") path))
+      (p (~tw :tokens "mt-2 text-stone-400 text-sm font-mono") path))
     (a
       :href "/sx/"
       :sx-get "/sx/"
@@ -15,6 +15,6 @@
       :sx-select "#sx-content"
       :sx-swap "outerHTML"
       :sx-push-url "true"
-      (~tw :tokens "inline-block mt-6 px-4 py-2 rounded border transition-colors")
-      :style (tw "text-violet-700 text-sm border-violet-200")
+      (~tw
+        :tokens "inline-block mt-6 px-4 py-2 rounded border transition-colors text-violet-700 text-sm border-violet-200")
       "Back to home")))

sx/sxc/init-client.sx.txt

@@ -20,9 +20,9 @@
     (log-info (str "cssx flush: running, rules:" (len (collected "cssx"))))
     (let ((rules (collected "cssx")))
       (when (not (empty? rules))
-        (let ((style (or (dom-query "[data-cssx]")
+        (let ((style (or (dom-query "[data-sx-css]")
                          (let ((s (dom-create-element "style" nil)))
-                           (dom-set-attr s "data-cssx" "")
+                           (dom-set-attr s "data-sx-css" "")
                            (dom-append-to-head s)
                            s))))
           (dom-set-prop style "textContent"