feat: Add UserStatusBadge showing subscription level and credits

New component in header shows:
- Subscription plan badge (Starter/Bronze/Silver/Gold with icons)
- AI credits balance with sparkle icon

Also includes SQL migration for user_subscriptions RLS fix

user_subscription_fix.sql

@@ -0,0 +1,33 @@
+-- Fix: Allow users to insert their own subscription on signup
+-- Run this in Supabase SQL Editor
+
+-- Option 1: Add INSERT policy for self-signup
+CREATE POLICY "user_subscriptions_insert_self" ON user_subscriptions 
+FOR INSERT WITH CHECK (
+  (SELECT auth.uid()) = user_id
+);
+
+-- Option 2 (better): Extend the existing handle_new_user trigger
+-- This automatically creates subscription when user registers
+CREATE OR REPLACE FUNCTION public.handle_new_user()
+RETURNS trigger AS $$
+BEGIN
+  -- Create profile
+  INSERT INTO public.profiles (id, username, avatar_url)
+  VALUES (
+    new.id, 
+    COALESCE(new.raw_user_meta_data->>'username', 'user_' || substr(new.id::text, 1, 8)), 
+    new.raw_user_meta_data->>'avatar_url'
+  )
+  ON CONFLICT (id) DO NOTHING;
+
+  -- Create subscription with starter plan
+  INSERT INTO public.user_subscriptions (user_id, plan_id)
+  SELECT 
+    new.id,
+    (SELECT id FROM subscription_plans WHERE name = 'starter' LIMIT 1)
+  ON CONFLICT (user_id) DO NOTHING;
+
+  RETURN new;
+END;
+$$ LANGUAGE plpgsql SECURITY DEFINER;