fix(auth): add profiles.email so signup trigger succeeds (#388)

[mutabalShawandar]

1. Related Issue

Fixes #388

2. Summary of Changes

Registering a new account fails with Database error saving new user (HTTP 500). The on_auth_user_created trigger calls handle_new_user(), which 20260911050000_user_onboarding.sql redefines to insert into public.profiles (id, email, full_name, timezone, onboarding_status, ...). The profiles table (20260906000000_create_profiles_table.sql) has no email column, and no migration adds one, so the insert fails and the signup is rolled back.

This PR adds a new migration, 20260918000000_add_profiles_email.sql, that:

• adds profiles.email (ADD COLUMN IF NOT EXISTS email TEXT)
• backfills existing rows from auth.users where email is NULL

3. Motivation & Context

New users cannot register on a database built from supabase/migrations/. The UI only shows the generic "Registration failed" message because signUpAction swallows the underlying error.

4. Implementation Details

• New file only: supabase/migrations/20260918000000_add_profiles_email.sql. No applied migration is edited, as CONTRIBUTING §14 asks.
• The column is nullable TEXT, matching what handle_new_user() writes (NEW.email).
• The migration is idempotent and non-destructive.
• No RLS changes. Existing profile policies are unchanged.
• Note: a fresh database also needs fix: migration 20260914 fails on a fresh database (relation "public.circle_members" does not exist) #387 to be fixed first, since 20260914 fails earlier.

5. Testing & Local Validation

• npm run lint not run (SQL-only change)
• npx tsc --noEmit not run (SQL-only change)
• npm test not run (SQL-only change)
• node scratch/secret-scan.mjs found 0 secrets
• npm run build not run (SQL-only change)

Manual verification: applied all migrations on a fresh local Supabase instance (with the #387 fix) and registered a new account. Signup succeeded and a profiles row was created with the email populated.

7. Database & Security Impact

• Database modifications included
  • Sequential migration added in supabase/migrations/
  • No RLS changes
  • No destructive schema changes

[vercel]

Someone is attempting to deploy a commit to the Vicky's projects Team on Vercel.

A member of the Team first needs to authorize it.

[TheVicky1]

It didn't passed all the Test Cases. Kindly go through it once and check it again.

I am closing this PR you can raise a new one with the correct code.

Thanks!