feat: Dynamic credit initialization based on subscription plan

New trigger creates:
- Profile (username from metadata)
- Subscription (starter plan by default)
- Credits (from plan's monthly_credits, not hardcoded)

Includes RLS policies for self-insert fallback

user_subscription_fix.sql

@@ -1,12 +1,14 @@
--- Fix for user registration trigger
+-- Dynamic Credit Initialization Migration
 -- Run this in Supabase SQL Editor
 
--- Simplified trigger - only creates profile, no subscription insert
--- (subscription is handled client-side after signup)
+-- Updated trigger: Creates profile, subscription, AND credits dynamically
 CREATE OR REPLACE FUNCTION public.handle_new_user()
 RETURNS trigger AS $$
+DECLARE
+    starter_plan_id UUID;
+    plan_credits INTEGER;
 BEGIN
-  -- Create profile only
+    -- Create profile
     INSERT INTO public.profiles (id, username, avatar_url)
     VALUES (
         new.id, 
@@ -15,6 +17,24 @@ BEGIN
     )
     ON CONFLICT (id) DO NOTHING;
 
+    -- Get starter plan ID and credits
+    SELECT id, monthly_credits INTO starter_plan_id, plan_credits
+    FROM subscription_plans 
+    WHERE name = 'starter' 
+    LIMIT 1;
+
+    -- Create subscription with starter plan
+    IF starter_plan_id IS NOT NULL THEN
+        INSERT INTO public.user_subscriptions (user_id, plan_id)
+        VALUES (new.id, starter_plan_id)
+        ON CONFLICT (user_id) DO NOTHING;
+    END IF;
+
+    -- Create user_credits with plan's monthly_credits
+    INSERT INTO public.user_credits (user_id, balance, total_purchased, total_used)
+    VALUES (new.id, COALESCE(plan_credits, 10), 0, 0)
+    ON CONFLICT (user_id) DO NOTHING;
+
     RETURN new;
 EXCEPTION WHEN OTHERS THEN
     -- Log but don't fail user creation
@@ -23,8 +43,30 @@ EXCEPTION WHEN OTHERS THEN
 END;
 $$ LANGUAGE plpgsql SECURITY DEFINER;
 
--- Allow users to insert their own subscription
-CREATE POLICY "user_subscriptions_insert_self" ON user_subscriptions 
-FOR INSERT WITH CHECK (
-  (SELECT auth.uid()) = user_id
-);
+-- RLS Policy for user_subscriptions insert (for client-side fallback)
+DO $$
+BEGIN
+    IF NOT EXISTS (
+        SELECT 1 FROM pg_policies 
+        WHERE schemaname = 'public' 
+        AND tablename = 'user_subscriptions' 
+        AND policyname = 'user_subscriptions_insert_self'
+    ) THEN
+        CREATE POLICY "user_subscriptions_insert_self" ON user_subscriptions 
+        FOR INSERT WITH CHECK ((SELECT auth.uid()) = user_id);
+    END IF;
+END $$;
+
+-- RLS Policy for user_credits insert (for lazy initialization fallback)
+DO $$
+BEGIN
+    IF NOT EXISTS (
+        SELECT 1 FROM pg_policies 
+        WHERE schemaname = 'public' 
+        AND tablename = 'user_credits' 
+        AND policyname = 'user_credits_insert_self'
+    ) THEN
+        CREATE POLICY "user_credits_insert_self" ON user_credits 
+        FOR INSERT WITH CHECK ((SELECT auth.uid()) = user_id);
+    END IF;
+END $$;