Build onboarding funnel widget (frontend)

[phertyameen]

Description

Build a funnel visualization showing conversion rate at each onboarding step, sourced from GET /analytics/onboarding/funnel, highlighting the step with the largest drop-off.

Why this matters

Onboarding drop-off is one of the fastest levers to improve activation, but only if the drop-off point is visible.

Files to touch

• frontend/src/components/analytics/OnboardingFunnelChart.tsx

Acceptance Criteria

• Each funnel step shows absolute count and conversion % from the previous step
• The step with the largest drop-off is visually highlighted

Notes

This issue is part of the new analytics module effort (tracking, aggregation,
and reporting on player/game activity). Please keep new code inside
backend/src/analytics/ following the same module/controller/service/provider
layout used by existing modules (e.g. progress, streak, quests).

[Okorie2000-code]

Hi maintainer, I will love to work on this issue. Please assign it to me.
I can submit a clean PR within 48hrs.

[Okorie2000-code]

Hi maintainer, I will love to work on this issue. Please assign it to me.
I can submit a clean PR within 48hrs.

[OluRemiFour]

Hi Maintainer,
Interested in working on this issue. I'll implement the requested changes and ensure everything is properly tested before submission.

Payout wallet (Stellar): GALHFNUOYOY4S5CNRK7OI7NKS7UNWYGSJII2POQ6XQKWMUVLKZ2SAWMP GrantFox OSS campaign — smart escrow payout on merge.