fix: Single source nav + dark logo support + customer settings debug

## ✅ Issue 1: Single Source of Truth for Navigation
**Problem:** Confusing dual nav sources (PHP + TypeScript fallback)
**Solution:** Removed static TypeScript fallback tree
**Result:** PHP NavigationRegistry is now the ONLY source
- More flexible (can check WooCommerce settings, extend via addons)
- Easier to maintain
- Clear error if backend data missing

## ✅ Issue 2: Logo in All Modes
**Already Working:** Header component renders in all modes
- Standalone ✅
- WP-Admin normal ✅
- WP-Admin fullscreen ✅

## ✅ Issue 5: Customer Settings 404 Debug
**Added:** Debug logging to track endpoint calls
**Note:** Routes are correctly registered
- May need WordPress permalinks flush
- Check debug.log for errors

## ✅ Issue 6: Dark Mode Logo Support
**Implemented:**
1. **Backend:**
   - Added `store_logo_dark` to branding endpoint
   - Returns both light and dark logos

2. **Header Component:**
   - Detects dark mode via MutationObserver
   - Switches logo based on theme
   - Falls back to light logo if dark not set

3. **Login Screen:**
   - Same dark mode detection
   - Theme-aware logo display
   - Seamless theme switching

4. **SVG Support:**
   - Already supported via `accept="image/*"`
   - Works for all image formats

**Result:** Perfect dark/light logo switching everywhere! 🌓

---

## Files Modified:
- `nav/tree.ts` - Removed static fallback
- `App.tsx` - Dark logo in header
- `Login.tsx` - Dark logo in login
- `StoreController.php` - Dark logo in branding endpoint + debug logs
- `Store.tsx` - Already has dark logo upload field
- `StoreSettingsProvider.php` - Already has dark logo backend

## Testing:
1. Upload dark logo in Store settings
2. Switch theme - logo should change
3. Check customer-settings endpoint in browser console
4. Verify nav items from PHP only

admin-spa/src/App.tsx

@@ -272,9 +272,30 @@ function AddonRoute({ config }: { config: any }) {
 function Header({ onFullscreen, fullscreen, showToggle = true, scrollContainerRef, onVisibilityChange }: { onFullscreen: () => void; fullscreen: boolean; showToggle?: boolean; scrollContainerRef?: React.RefObject<HTMLDivElement>; onVisibilityChange?: (visible: boolean) => void }) {
   const [siteTitle, setSiteTitle] = React.useState((window as any).wnw?.siteTitle || 'WooNooW');
   const [storeLogo, setStoreLogo] = React.useState('');
+  const [storeLogoDark, setStoreLogoDark] = React.useState('');
   const [isVisible, setIsVisible] = React.useState(true);
   const lastScrollYRef = React.useRef(0);
   const isStandalone = window.WNW_CONFIG?.standaloneMode ?? false;
+  const [isDark, setIsDark] = React.useState(false);
+  
+  // Detect dark mode
+  React.useEffect(() => {
+    const checkDarkMode = () => {
+      const htmlEl = document.documentElement;
+      setIsDark(htmlEl.classList.contains('dark'));
+    };
+    
+    checkDarkMode();
+    
+    // Watch for theme changes
+    const observer = new MutationObserver(checkDarkMode);
+    observer.observe(document.documentElement, {
+      attributes: true,
+      attributeFilter: ['class']
+    });
+    
+    return () => observer.disconnect();
+  }, []);
   
   // Notify parent of visibility changes
   React.useEffect(() => {
@@ -289,6 +310,7 @@ function Header({ onFullscreen, fullscreen, showToggle = true, scrollContainerRe
         if (response.ok) {
           const data = await response.json();
           if (data.store_logo) setStoreLogo(data.store_logo);
+          if (data.store_logo_dark) setStoreLogoDark(data.store_logo_dark);
           if (data.store_name) setSiteTitle(data.store_name);
         }
       } catch (err) {
@@ -302,6 +324,7 @@ function Header({ onFullscreen, fullscreen, showToggle = true, scrollContainerRe
   React.useEffect(() => {
     const handleStoreUpdate = (event: CustomEvent) => {
       if (event.detail?.store_logo) setStoreLogo(event.detail.store_logo);
+      if (event.detail?.store_logo_dark) setStoreLogoDark(event.detail.store_logo_dark);
       if (event.detail?.store_name) setSiteTitle(event.detail.store_name);
     };
     
@@ -358,11 +381,14 @@ function Header({ onFullscreen, fullscreen, showToggle = true, scrollContainerRe
     return null;
   }
   
+  // Choose logo based on theme
+  const currentLogo = isDark && storeLogoDark ? storeLogoDark : storeLogo;
+  
   return (
     <header className={`h-16 border-b border-border flex items-center px-4 justify-between sticky ${fullscreen ? `top-0` : `top-[32px]`} z-40 bg-background md:bg-background/95 md:backdrop-blur md:supports-[backdrop-filter]:bg-background/60 transition-transform duration-300 ${fullscreen && !isVisible ? '-translate-y-full md:translate-y-0' : 'translate-y-0'}`}>
       <div className="flex items-center gap-3">
-        {storeLogo ? (
-          <img src={storeLogo} alt={siteTitle} className="h-8 object-contain" />
+        {currentLogo ? (
+          <img src={currentLogo} alt={siteTitle} className="h-8 object-contain" />
         ) : (
           <div className="font-semibold">{siteTitle}</div>
         )}