feat: add navigation for admin portal

Add 'Venue Admin' menu item in hamburger navigation:
- Links to /admin/clubs for facility management
- Purple accent to distinguish from player features
- Positioned after assessment, before language selector

Add tabs to club detail page:
- Plans tab (purple accent)
- Members tab (purple accent)
- Settings tab (purple accent)
- All tabs link to new admin portal pages

Navigation is now complete for accessing all facility management features.

src/app/[locale]/admin/clubs/[club_id]/ClubDetailTabs.tsx

@@ -196,6 +196,24 @@ export default function ClubDetailTabs({ clubId }: ClubDetailTabsProps) {
           >
             Slot Definitions
           </Link>
+          <Link
+            href={`/${locale}/admin/clubs/${clubId}/plans`}
+            className="px-6 py-3 font-semibold text-purple-600 hover:text-purple-700 hover:border-purple-300 transition-colors border-b-2 border-transparent"
+          >
+            Plans
+          </Link>
+          <Link
+            href={`/${locale}/admin/clubs/${clubId}/members`}
+            className="px-6 py-3 font-semibold text-purple-600 hover:text-purple-700 hover:border-purple-300 transition-colors border-b-2 border-transparent"
+          >
+            Members
+          </Link>
+          <Link
+            href={`/${locale}/admin/clubs/${clubId}/settings`}
+            className="px-6 py-3 font-semibold text-purple-600 hover:text-purple-700 hover:border-purple-300 transition-colors border-b-2 border-transparent"
+          >
+            Settings
+          </Link>
         </div>
       </div>
 

src/components/Navigation.tsx

@@ -409,6 +409,27 @@ export default function Navigation({ pageTitle }: NavigationProps) {
                       <span className="font-medium text-slate-900">{t("What's my level?")}</span>
                     </Link>
                   </motion.div>
+
+                  {/* Admin Section */}
+                  <div className="my-4 border-t border-slate-100"></div>
+
+                  <motion.div
+                    custom={4}
+                    variants={menuItemVariants}
+                    initial="closed"
+                    animate="open"
+                  >
+                    <Link
+                      href={localizedLink("/admin/clubs")}
+                      onClick={closeMenu}
+                      className="flex items-center space-x-3 p-4 rounded-xl hover:bg-slate-50 transition-colors duration-200 group"
+                    >
+                      <div className="p-2 rounded-lg bg-purple-100 group-hover:bg-purple-200 transition-colors duration-200">
+                        <Settings className="w-5 h-5 text-purple-700" />
+                      </div>
+                      <span className="font-medium text-slate-900">{t('Venue Admin')}</span>
+                    </Link>
+                  </motion.div>
                     </>
                   )}
 
@@ -416,7 +437,7 @@ export default function Navigation({ pageTitle }: NavigationProps) {
                   <div className="my-4 border-t border-slate-100"></div>
 
                   <motion.div
-                    custom={isLoggedIn ? 4 : 2}
+                    custom={isLoggedIn ? 5 : 2}
                     variants={menuItemVariants}
                     initial="closed"
                     animate="open"
@@ -476,7 +497,7 @@ export default function Navigation({ pageTitle }: NavigationProps) {
                   {isLoggedIn && (
                     <div className="flex items-center gap-3">
                       <motion.div
-                        custom={5}
+                        custom={6}
                         variants={menuItemVariants}
                         initial="closed"
                         animate="open"
@@ -494,7 +515,7 @@ export default function Navigation({ pageTitle }: NavigationProps) {
                         </Link>
                       </motion.div>
                       <motion.div
-                        custom={6}
+                        custom={7}
                         variants={menuItemVariants}
                         initial="closed"
                         animate="open"