feat: Operator analytics dashboard (funnel, retention, conversion)

[joelpeace48-cell]

Background & current state

Operators lack a consolidated performance view. Analytics charts are tracked (#523), and rollups are proposed (NEW-026), but there's no funnel/retention/conversion dashboard sourced from the indexed source of truth.

Goal

Build an operator analytics dashboard showing the registration→credit→claim funnel, retention cohorts, and conversion over time, backed by indexed rollups.

Technical design

• Backend: dashboard endpoints over rollups (NEW-026): funnel counts, conversion rates, time series. Frontend: charts (build on perf: Campaign analytics — real-time charts with on-chain + API data #523/CampaignAnalytics.jsx).
• Reconcile against raw indexed events within tolerance; include as_of_ledger freshness.

Edge cases

• Sparse data / new campaigns → graceful empties.
• Large ranges → downsampling.
• Reconciliation drift → flag if beyond tolerance.

Task breakdown

• Dashboard endpoints over rollups.
• Frontend funnel + retention + conversion views.
• Reconciliation test vs raw events.

Acceptance criteria

• Metrics match the indexed source-of-truth within tolerance; funnel/retention/conversion render.

Testing & verification

• Reconciliation test vs raw events; snapshot of dashboard.

Out of scope

• Cohort API internals (NEW-100) — consumed here.

Dependencies / related

• Requires NEW-024/026; builds on perf: Campaign analytics — real-time charts with on-chain + API data #523; uses NEW-100.

Difficulty: medium · Effort: M · performance