Convert post edit form from raw HTML to SX expressions

Replace _post_edit_content_sx raw HTML builder with sx_call() pattern
matching render_editor_panel. Add ~blog-editor-edit-form,
~blog-editor-publish-js, ~blog-editor-sx-initial components to
editor.sx. Fixes (~sx-editor-styles) rendering as literal text on
the edit page.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

blog/sx/editor.sx

@@ -55,6 +55,108 @@
       (button :type "submit"
         :class "px-[20px] py-[6px] bg-stone-700 text-white text-[14px] rounded-[8px] hover:bg-stone-800 transition-colors cursor-pointer" create-label))))
 
+;; Edit form — pre-populated version for /<slug>/admin/edit/
+(defcomp ~blog-editor-edit-form (&key csrf updated-at title-val excerpt-val
+                                      feature-image feature-image-caption
+                                      sx-content-val lexical-json
+                                      has-sx title-placeholder
+                                      status already-emailed
+                                      newsletter-options footer-extra)
+  (let* ((sel-cls "text-[14px] rounded-[4px] border border-stone-200 px-[8px] py-[6px] bg-white text-stone-600")
+         (active "px-[12px] py-[6px] text-[13px] font-medium text-stone-700 border-b-2 border-stone-700 cursor-pointer bg-transparent")
+         (inactive "px-[12px] py-[6px] text-[13px] font-medium text-stone-400 border-b-2 border-transparent cursor-pointer bg-transparent hover:text-stone-600"))
+    (form :id "post-edit-form" :method "post" :class "max-w-[768px] mx-auto pb-[48px]"
+      (input :type "hidden" :name "csrf_token" :value csrf)
+      (input :type "hidden" :name "updated_at" :value updated-at)
+      (input :type "hidden" :id "lexical-json-input" :name "lexical" :value "")
+      (input :type "hidden" :id "sx-content-input" :name "sx_content" :value (or sx-content-val ""))
+      (input :type "hidden" :id "feature-image-input" :name "feature_image" :value (or feature-image ""))
+      (input :type "hidden" :id "feature-image-caption-input" :name "feature_image_caption" :value (or feature-image-caption ""))
+      (div :id "feature-image-container" :class "relative mt-[16px] mb-[24px] group"
+        (div :id "feature-image-empty" :class (if feature-image "hidden" "")
+          (button :type "button" :id "feature-image-add-btn"
+            :class "text-[14px] text-stone-400 hover:text-stone-600 transition-colors cursor-pointer"
+            "+ Add feature image"))
+        (div :id "feature-image-filled" :class (str "relative " (if feature-image "" "hidden"))
+          (img :id "feature-image-preview" :src (or feature-image "") :alt ""
+            :class "w-full max-h-[448px] object-cover rounded-[8px] cursor-pointer")
+          (button :type "button" :id "feature-image-delete-btn"
+            :class "absolute top-[8px] right-[8px] w-[32px] h-[32px] rounded-full bg-black/50 text-white flex items-center justify-center opacity-0 group-hover:opacity-100 transition-opacity hover:bg-black/70 cursor-pointer text-[14px]"
+            :title "Remove feature image"
+            (i :class "fa-solid fa-trash-can"))
+          (input :type "text" :id "feature-image-caption" :value (or feature-image-caption "")
+            :placeholder "Add a caption..."
+            :class "mt-[8px] w-full text-[14px] text-stone-500 bg-transparent border-none outline-none placeholder:text-stone-300 focus:text-stone-700"))
+        (div :id "feature-image-uploading"
+          :class "hidden flex items-center gap-[8px] mt-[8px] text-[14px] text-stone-400"
+          (i :class "fa-solid fa-spinner fa-spin") " Uploading...")
+        (input :type "file" :id "feature-image-file"
+          :accept "image/jpeg,image/png,image/gif,image/webp,image/svg+xml" :class "hidden"))
+      (input :type "text" :name "title" :value (or title-val "") :placeholder title-placeholder
+        :class "w-full text-[36px] font-bold bg-transparent border-none outline-none placeholder:text-stone-300 mb-[8px] leading-tight")
+      (textarea :name "custom_excerpt" :rows "1" :placeholder "Add an excerpt..."
+        :class "w-full text-[18px] text-stone-500 bg-transparent border-none outline-none placeholder:text-stone-300 resize-none mb-[24px] leading-relaxed"
+        (or excerpt-val ""))
+      ;; Editor tabs
+      (div :class "flex gap-[4px] mb-[8px] border-b border-stone-200"
+        (button :type "button" :id "editor-tab-sx"
+          :class (if has-sx active inactive)
+          :onclick "document.getElementById('sx-editor').style.display='block';document.getElementById('lexical-editor').style.display='none';this.className='px-[12px] py-[6px] text-[13px] font-medium text-stone-700 border-b-2 border-stone-700 cursor-pointer bg-transparent';document.getElementById('editor-tab-koenig').className='px-[12px] py-[6px] text-[13px] font-medium text-stone-400 border-b-2 border-transparent cursor-pointer bg-transparent hover:text-stone-600'"
+          "SX Editor")
+        (button :type "button" :id "editor-tab-koenig"
+          :class (if has-sx inactive active)
+          :onclick "document.getElementById('lexical-editor').style.display='block';document.getElementById('sx-editor').style.display='none';this.className='px-[12px] py-[6px] text-[13px] font-medium text-stone-700 border-b-2 border-stone-700 cursor-pointer bg-transparent';document.getElementById('editor-tab-sx').className='px-[12px] py-[6px] text-[13px] font-medium text-stone-400 border-b-2 border-transparent cursor-pointer bg-transparent hover:text-stone-600'"
+          "Koenig (Legacy)"))
+      (div :id "sx-editor" :class "relative w-full bg-transparent"
+        :style (if has-sx "" "display:none"))
+      (div :id "lexical-editor" :class "relative w-full bg-transparent"
+        :style (if has-sx "display:none" ""))
+      ;; Initial lexical JSON
+      (script :id "lexical-initial-data" :type "application/json" lexical-json)
+      ;; Footer: status + publish mode + newsletter + save + badges
+      (div :class "flex flex-wrap items-center gap-[16px] mt-[32px] pt-[16px] border-t border-stone-200"
+        (select :id "status-select" :name "status" :class sel-cls
+          (option :value "draft" :selected (= status "draft") "Draft")
+          (option :value "published" :selected (= status "published") "Published"))
+        (select :id "publish-mode-select" :name "publish_mode"
+          :class (str sel-cls (if (= status "published") "" " hidden")
+                              (if already-emailed " opacity-50 pointer-events-none" ""))
+          :disabled (if already-emailed true nil)
+          (option :value "web" :selected true "Web only")
+          (option :value "email" "Email only")
+          (option :value "both" "Web + Email"))
+        (select :id "newsletter-select" :name "newsletter_slug"
+          :class (str sel-cls " hidden")
+          :disabled (if already-emailed true nil)
+          newsletter-options)
+        (button :type "submit"
+          :class "px-[20px] py-[6px] bg-stone-700 text-white text-[14px] rounded-[8px] hover:bg-stone-800 transition-colors cursor-pointer"
+          "Save")
+        (when footer-extra footer-extra)))))
+
+;; Publish-mode show/hide script for edit form
+(defcomp ~blog-editor-publish-js (&key already-emailed)
+  (script
+    "(function() {"
+    "  var statusSel = document.getElementById('status-select');"
+    "  var modeSel = document.getElementById('publish-mode-select');"
+    "  var nlSel = document.getElementById('newsletter-select');"
+    (str "  var alreadyEmailed = " (if already-emailed "true" "false") ";")
+    "  function sync() {"
+    "    var isPublished = statusSel.value === 'published';"
+    "    if (isPublished && !alreadyEmailed) { modeSel.classList.remove('hidden'); } else { modeSel.classList.add('hidden'); }"
+    "    var needsEmail = isPublished && !alreadyEmailed && (modeSel.value === 'email' || modeSel.value === 'both');"
+    "    if (needsEmail) { nlSel.classList.remove('hidden'); } else { nlSel.classList.add('hidden'); }"
+    "  }"
+    "  statusSel.addEventListener('change', sync);"
+    "  modeSel.addEventListener('change', sync);"
+    "  sync();"
+    "})();"))
+
+;; SX initial content script for edit form
+(defcomp ~blog-editor-sx-initial (&key sx-content)
+  (script (str "window.__SX_INITIAL__ = '" sx-content "' || null;")))
+
 (defcomp ~blog-editor-styles (&key css-href)
   (<> (link :rel "stylesheet" :href css-href)
     (style