fix: branding save uses API directly (not form POST) — reliable Supabase persistence

Problem: Form POST to same page required PHP session + page re-render.
Save appeared to work but values weren't persisting to Supabase reliably.

Fix: Save button now POSTs to /api/branding.php directly as JSON.
- Collects all input values from DOM
- Sends { action: 'save_theme', values: { key: value, ... } }
- API writes each value to platform_theme table (upsert)
- No session dependency, no form submission, no page reload
- Response confirms success/failure with message

On page refresh: PHP reads from platform_theme → shows saved values ✅Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

admin/branding.php

@@ -539,29 +539,42 @@ function saveAll() {
   saveBtn.textContent = 'Saving...';
   saveBtn.style.opacity = '0.6';
 
-  const form = document.querySelector('form[method="POST"]:not([enctype])');
-  if (!form) return;
-  const formData = new FormData(form);
-  formData.append('save_theme', '1');
-
-  fetch(window.location.href, { method: 'POST', body: formData })
-    .then(r => {
-      if (r.ok) {
+  // Collect all theme values from inputs
+  const values = {};
+  document.querySelectorAll('input[name^="theme["]').forEach(input => {
+    const match = input.name.match(/theme\[(.+?)\]/);
+    if (match && input.value) {
+      values[match[1]] = input.value;
+    }
+  });
+
+  // Save directly to Supabase via API (reliable, no session dependency)
+  fetch('/api/branding.php', {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify({ action: 'save_theme', values })
+  })
+    .then(r => r.json())
+    .then(data => {
+      if (data.success) {
         hasChanges = false;
         saveBtn.textContent = '✓ Saved!';
         saveBtn.style.opacity = '0.5';
         saveBtn.style.pointerEvents = 'none';
-        saveStatus.textContent = '✓ All changes saved';
+        saveStatus.textContent = '✓ All changes saved to database';
         saveStatus.style.color = '#34D399';
         setTimeout(() => {
           saveBtn.textContent = '💾 Save All';
           saveStatus.textContent = 'No unsaved changes';
           saveStatus.style.color = '#64748b';
         }, 2000);
+      } else {
+        saveBtn.textContent = '❌ Error: ' + (data.error || 'unknown');
+        saveBtn.style.opacity = '1';
       }
     })
-    .catch(() => {
-      saveBtn.textContent = '❌ Error — retry';
+    .catch((err) => {
+      saveBtn.textContent = '❌ Network error — retry';
       saveBtn.style.opacity = '1';
     });
 }