Fix subscription tier and domain_limit issues

- Changed SubscriptionTier.STARTER to SCOUT (correct tier name)
- Removed domain_limit from Subscription constructor (it's a computed property)
- Database needs to be re-initialized with: python scripts/init_db.py && python scripts/seed_tld_prices.py

backend/app/api/domains.py

@@ -60,7 +60,7 @@ async def add_domain(
     if current_user.subscription:
         limit = current_user.subscription.max_domains
     else:
-        limit = TIER_CONFIG[SubscriptionTier.STARTER]["domain_limit"]
+        limit = TIER_CONFIG[SubscriptionTier.SCOUT]["domain_limit"]
     
     current_count = len(current_user.domains)
     

backend/app/services/auth.py

@@ -98,12 +98,11 @@ class AuthService:
         db.add(user)
         await db.flush()
         
-        # Create default starter subscription
+        # Create default Scout (free) subscription
         subscription = Subscription(
             user_id=user.id,
-            tier=SubscriptionTier.STARTER,
+            tier=SubscriptionTier.SCOUT,
             status=SubscriptionStatus.ACTIVE,
-            domain_limit=TIER_CONFIG[SubscriptionTier.STARTER]["domain_limit"],
         )
         db.add(subscription)