refactor: Smart contextual headers - only when they add value

Implemented intelligent header rules based on user feedback.

Problem Analysis:
1. Dashboard submenu tabs already show page names (Overview, Revenue, Orders...)
2. Showing "Orders" header is ambiguous (Analytics or Management?)
3. Wasted vertical space for redundant information
4. FAB already handles actions on management pages

Solution: Headers ONLY When They Add Value

Rules Implemented:

1. Dashboard Pages: NO HEADERS
   - Submenu tabs are sufficient
   - Saves vertical space
   - No ambiguity

   Before:
   Dashboard → Overview  = "Dashboard" header (redundant!)
   Dashboard → Orders    = "Orders" header (confusing!)

   After:
   Dashboard → Overview  = No header (tabs show "Overview")
   Dashboard → Orders    = No header (tabs show "Orders")

2. Settings Pages: HEADERS ONLY WITH ACTIONS
   - Store Details + [Save] = Show header ✓
   - Payments + [Refresh]   = Show header ✓
   - Pages without actions  = No header (save space)

   Logic: If there is an action button, we need a place to put it → header
          If no action button, header is just wasting space → remove it

3. Management Pages: NO HEADERS
   - FAB handles actions ([+ Add Order])
   - No need for redundant header with action button

4. Payments Exception: REMOVED
   - Treat Payments like any other settings page
   - Has action (Refresh) = show header
   - Consistent with other pages

Implementation:

Dashboard Pages (7 files):
- Removed usePageHeader hook
- Removed useEffect for setting header
- Removed unused imports (useEffect, usePageHeader)
- Result: Clean, no headers, tabs are enough

PageHeader Component:
- Removed Payments special case detection
- Removed useLocation import
- Simplified logic: hideOnDesktop prop only

SettingsLayout Component:
- Changed logic: Only set header when onSave OR action exists
- If no action: clearPageHeader() instead of setPageHeader(title)
- Result: Headers only appear when needed

Benefits:

✅ Saves vertical space (no redundant headers)
✅ No ambiguity (Dashboard Orders vs Orders Management)
✅ Consistent logic (action = header, no action = no header)
✅ Cleaner UI (less visual clutter)
✅ FAB handles management page actions

Files Modified:
- Dashboard/index.tsx (Overview)
- Dashboard/Revenue.tsx
- Dashboard/Orders.tsx
- Dashboard/Products.tsx
- Dashboard/Customers.tsx
- Dashboard/Coupons.tsx
- Dashboard/Taxes.tsx
- PageHeader.tsx
- SettingsLayout.tsx

Result: Smart headers that only appear when they add value! 🎯

admin-spa/src/routes/Settings/components/SettingsLayout.tsx

@@ -35,7 +35,8 @@ export function SettingsLayout({
     }
   };
 
-  // Set page header when component mounts
+  // Set page header ONLY when there's an action (Save button or custom action)
+  // This saves vertical space on pages without actions
   useEffect(() => {
     if (onSave) {
       setPageHeader(
@@ -59,8 +60,8 @@ export function SettingsLayout({
       // If there's a custom action, use it
       setPageHeader(title, action);
     } else {
-      // Always set the title, even without action
-      setPageHeader(title);
+      // No action = no header (save vertical space)
+      clearPageHeader();
     }
 
     return () => clearPageHeader();