fix auth: register redirect, password reset flow, GHL contact ID, session handling

- Fix register redirect bug where successful signup returned 400 instead
  of redirecting to /account/setup (use isRedirect() to re-throw redirects)
- Add error display to register page and fix Svelte 5 syntax (on:click)
- Add await to Google sign-in on login page and register page
- Fix logout to await signOut and redirect to /
- Implement full password reset flow:
  - Add sendResetPassword callback to auth.ts config
  - Create forgot-password page with email submission
  - Create reset-password page with one-time token validation
  - Guard reset page: redirect to / if no valid token in URL
- Add ghlContactId field to Profile model for future Go High Level integration
- Add Prisma migration for ghl_contact_id column
- Update register test to expect redirect instead of broken 400

prisma/migrations/20260707132629_add_ghl_contact_id/migration.sql

@@ -0,0 +1,2 @@
+-- AlterTable
+ALTER TABLE "Profile" ADD COLUMN     "ghl_contact_id" TEXT;