feat: add vendor registration success screen

[EmeditWeb]

Problem

After successful vendor registration, VendorRegister.tsx (line 42) navigates to /vendors (the browse-vendors page). There is no success state, congratulations message, or onboarding guidance. The vendor is left wondering "what next?"

User impact: New vendors don't know their registration was successful or what to do next (set up products, wait for approval, etc.).

Root Cause

The post-registration flow was never implemented.

What To Build

1. Add a success screen after registration showing:
   • "Registration submitted for review" message
   • Vendor status badge (pending approval)
   • Next steps: "Add products while you wait"
   • Link to vendor dashboard
2. Replace the /vendors redirect with the success screen

Files To Touch

• src/pages/VendorRegister.tsx — line 42 replace redirect

Acceptance Criteria

• Success screen shown after registration
• Shows vendor status, next steps, dashboard link
• Auto-redirects to dashboard after 5 seconds (optional)

Mandatory Checks

• context/ files read
• npm run build passes
• PR references this issue

[Deylan-S]

Hi there! I'd like to work on this issue. I can implement the new post-registration success screen in VendorRegister.tsx, add the status badge along with the next steps, and handle the optional 5-second auto-redirect to the dashboard. Please assign it to me. Thanks!