fix: Use upsert for profile updates to handle missing rows

Changes:
1. Created migration 003_fix_profile_creation.sql:
   - Added INSERT policy for profiles table
   - Made username nullable with default value
   - Created upsert_profile function for safe upserts

2. Updated ProfileSettings.tsx:
   - Changed from .update() to .upsert()
   - Added id field to upsert data
   - Added loadProfile() call after save to refresh state

This fixes the issue where users couldn't update their profile
because no profile row existed in the database.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

supabase/migrations/003_fix_profile_creation.sql

@@ -0,0 +1,82 @@
+-- ========================================
+-- Fix Profile Creation Issue
+-- ========================================
+-- Adds INSERT policy and function to handle profile creation
+
+-- Add INSERT policy for profiles
+DROP POLICY IF EXISTS "Users can insert their own profile" ON public.profiles;
+
+CREATE POLICY "Users can insert their own profile"
+  ON public.profiles FOR INSERT
+  WITH CHECK (auth.uid() = id);
+
+-- Make username nullable and add default
+ALTER TABLE public.profiles
+  ALTER COLUMN username DROP NOT NULL;
+
+ALTER TABLE public.profiles
+  ALTER COLUMN username SET DEFAULT '';
+
+-- Create function to handle profile upsert
+CREATE OR REPLACE FUNCTION public.upsert_profile(
+  p_user_id UUID,
+  p_username TEXT DEFAULT '',
+  p_full_name TEXT DEFAULT '',
+  p_bio TEXT DEFAULT '',
+  p_phone_number TEXT DEFAULT '',
+  p_location TEXT DEFAULT '',
+  p_website TEXT DEFAULT '',
+  p_language TEXT DEFAULT 'en',
+  p_theme TEXT DEFAULT 'dark'
+)
+RETURNS SETOF public.profiles AS $$
+BEGIN
+  RETURN QUERY
+  INSERT INTO public.profiles (
+    id,
+    username,
+    full_name,
+    bio,
+    phone_number,
+    location,
+    website,
+    language,
+    theme,
+    updated_at
+  )
+  VALUES (
+    p_user_id,
+    p_username,
+    p_full_name,
+    p_bio,
+    p_phone_number,
+    p_location,
+    p_website,
+    p_language,
+    p_theme,
+    NOW()
+  )
+  ON CONFLICT (id)
+  DO UPDATE SET
+    username = COALESCE(NULLIF(EXCLUDED.username, ''), public.profiles.username),
+    full_name = EXCLUDED.full_name,
+    bio = EXCLUDED.bio,
+    phone_number = EXCLUDED.phone_number,
+    location = EXCLUDED.location,
+    website = EXCLUDED.website,
+    language = EXCLUDED.language,
+    theme = EXCLUDED.theme,
+    updated_at = NOW()
+  RETURNING *;
+END;
+$$ LANGUAGE plpgsql SECURITY DEFINER;
+
+-- Grant execute permission to authenticated users
+GRANT EXECUTE ON FUNCTION public.upsert_profile TO authenticated;
+
+-- Success message
+DO $$
+BEGIN
+  RAISE NOTICE 'Profile creation fix applied successfully!';
+  RAISE NOTICE 'Users can now create and update their profiles.';
+END $$;