Fix stepper: restore source as string, clean def-store application

Previous sed edits corrupted the file. Restored from 5c8b05a and
applied only the def-store change cleanly via python (no sed/sx-tools).

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

sx/sx/home-stepper.sx

@@ -3,14 +3,8 @@
   ()
   (let
     ((source "(div (~cssx/tw :tokens \"text-center\")\n  (h1 (~cssx/tw :tokens \"text-3xl font-bold mb-2\")\n    (span (~cssx/tw :tokens \"text-rose-500\") \"the \")\n    (span (~cssx/tw :tokens \"text-amber-500\") \"joy \")\n    (span (~cssx/tw :tokens \"text-emerald-500\") \"of \")\n    (span (~cssx/tw :tokens \"text-violet-600 text-4xl\") \"sx\")))")
-  (h1 (~cssx/tw :tokens "text-3xl font-bold mb-2")
-    (span (~cssx/tw :tokens "text-rose-500") "the ")
-    (span (~cssx/tw :tokens "text-amber-500") "joy ")
-    (span (~cssx/tw :tokens "text-emerald-500") "of ")
-    (span (~cssx/tw :tokens "text-violet-600 text-4xl") "sx")))")
-      (store
-        (if (client?) (def-store "home-stepper" (fn () {:step-idx (signal 9)})) nil))
       (steps (signal (list)))
+      (store (if (client?) (def-store "home-stepper" (fn () {:step-idx (signal 9)})) nil))
       (step-idx (if store (get store "step-idx") (signal 9)))
       (dom-stack-sig (signal (list)))
       (code-tokens (signal (list))))
@@ -271,7 +265,17 @@
                 ((target (- (deref step-idx) 1)))
                 (rebuild-preview target)
                 (reset! step-idx target)
-                (update-code-highlight))))))
+                (update-code-highlight)
+)))))
+
+      (let
+        ((saved (get-cookie "sx-home-stepper")))
+        (when
+          saved
+          (thaw-from-sx saved)
+          (when
+            (or (< (deref step-idx) 0) (> (deref step-idx) 16))
+            (reset! step-idx 9))))
       (let
         ((parsed (sx-parse source)))
         (when
@@ -317,7 +321,10 @@
           (div
             :class "flex items-center justify-center gap-2 md:gap-3"
             (button
-              :on-click (fn (e) (do-back))
+              :on-click (fn
+                (e)
+                (do-back)
+)
               :class (str
                 "px-2 py-1 rounded text-3xl "
                 (if
@@ -331,7 +338,10 @@
               " / "
               (len (deref steps)))
             (button
-              :on-click (fn (e) (do-step))
+              :on-click (fn
+                (e)
+                (do-step)
+)
               :class (str
                 "px-2 py-1 rounded text-3xl "
                 (if