fix: Submenu active state + currency symbols + flags integration

1. Fixed Submenu Active State ✅
   Problem: First submenu always active due to pathname.startsWith()
   - /dashboard matches /dashboard/analytics
   - Both items show as active

   Solution: Use exact match instead
   - const isActive = pathname === it.path
   - Only clicked item shows as active

   Files: DashboardSubmenuBar.tsx, SubmenuBar.tsx

2. Fixed Currency Symbol Display ✅
   Problem: HTML entities showing (ءإ)
   Solution: Use currency code when symbol has HTML entities

   Before: United Arab Emirates dirham (ءإ)
   After: United Arab Emirates dirham (AED)

   Logic:
   const displaySymbol = (!currency.symbol || currency.symbol.includes('&#'))
     ? currency.code
     : currency.symbol;

3. Integrated Flags.json ✅

   A. Moved flags.json to admin-spa/src/data/
   B. Added flag support to SearchableSelect component
      - New icon prop in Option interface
      - Displays flag before label in trigger
      - Displays flag before label in dropdown

   C. Currency select now shows flags
      - Flag icon next to each currency
      - Visual country identification
      - Better UX for currency selection

   D. Dynamic store summary with flag
      Before: 🇮🇩 Your store is located in Indonesia
      After: [FLAG] Your store is located in Indonesia

      - Flag based on selected currency
      - Country name from flags.json
      - Currency name (not just code)
      - Dynamic updates when currency changes

Benefits:
✅ Clear submenu navigation
✅ Readable currency symbols
✅ Visual country flags
✅ Better currency selection UX
✅ Dynamic store location display

Files Modified:
- DashboardSubmenuBar.tsx: Exact match for active state
- SubmenuBar.tsx: Exact match for active state
- Store.tsx: Currency symbol fix + flags integration
- searchable-select.tsx: Icon support
- flags.json: Moved to admin-spa/src/data/

admin-spa/src/components/nav/SubmenuBar.tsx

@@ -17,9 +17,8 @@ export default function SubmenuBar({ items = [] }: Props) {
         <div className="flex gap-2 overflow-x-auto no-scrollbar">
           {items.map((it) => {
             const key = `${it.label}-${it.path || it.href}`;
-            const isActive = !!it.path && (
-              it.exact ? pathname === it.path : pathname.startsWith(it.path)
-            );
+            // Fix: Always use exact match to prevent first submenu from being always active
+            const isActive = !!it.path && pathname === it.path;
             const cls = [
               'inline-flex items-center gap-2 rounded-md px-2.5 py-1.5 border text-sm whitespace-nowrap',
               'focus:outline-none focus:ring-0 focus:shadow-none',