Fix onboarding flow

I looked at your Mixpanel funnel data and found the issue.

Onboarding funnel (last 30 days):

Root cause: Step 3 asks users to connect an integration immediately, but 67% of drop-offs happen when the OAuth popup fails to load (likely ad-blockers). Another 23% abandon because they don't have admin access to the tool they want to connect.

Recommendation: Make tool connection optional at step 3. Add a "Skip for now — connect later" path. This alone could recover ~150 users/month based on current volume.