feat: implement Protocol Analytics & Reporting API

[Netty-kun]

Overview

This PR adds a production-ready Protocol Analytics & Reporting API for TruthBounty. It centralises aggregation of protocol, user, verification, governance, and financial metrics, exposes dashboard summaries and historical trend endpoints, supports filtered/exportable reports, and provides monitoring metrics — all built on Redis caching and pre-computed aggregates for consistent, performant responses.

Related Issue

Closes #BE-023

Changes

📊 Protocol Analytics Engine

• [ADD] src/analytics/analytics.module.ts — wires the analytics service, controller, DTOs, and response interfaces.
• [ADD] src/analytics/analytics.service.ts
  • Aggregates claims, verifications, disputes, staking, rewards, governance, reputation, and user metrics.
  • Supports multiple aggregation periods (hourly, daily, weekly, monthly) and configurable time-range filters.
  • Pre-computes dashboard summaries and historical trends.
  • Asynchronously generates and exports reports (CSV/JSON).
• [ADD] src/analytics/analytics.controller.ts
  • REST endpoints for dashboard summary, historical reporting, trend analysis, filtered exports, and monitoring metrics.
  • Returns standardised response objects with pagination, timestamps, and request IDs.
• [ADD] src/analytics/dto/analytics-query.dto.ts — validated query parameters for aggregation periods, filters, pagination, and export format.
• [ADD] src/analytics/interfaces/analytics-response.interface.ts — shared interfaces for analytics data, metadata, pagination, and error responses.
• [ADD] src/aggregation/aggregation.types.ts — shared metric type definitions and aggregation period enums.
• [MODIFY] prisma/schema.prisma — adds analytics aggregation tables, indexes for pre-computed metrics, and scheduled refresh state.
• [ADD] Monitoring metrics for report generation time, query latency, cache hit ratio, refresh duration, export requests, and failed report generation.
• [ADD] Unit and integration tests covering metric aggregation, dashboard generation, export, filtering, pagination, historical reporting, cache behavior, concurrent requests, monitoring metrics, and performance benchmarks.

Verification Results

npm test -- --testPathPattern=src/analytics
✅ 68/68 tests passed

Acceptance checks:
✅ Protocol metrics computed correctly (claims, verifications, disputes, staking, governance, financial)
✅ Historical reporting works across daily/weekly/monthly periods
✅ Dashboard summaries available at /analytics/dashboard
✅ Reports exported in CSV and JSON
✅ Performance targets met (p95 < 250ms with Redis cache)
✅ Monitoring metrics exposed at /analytics/metrics

Acceptance Criteria	Status
Protocol metrics are computed correctly	✅ Verified across all metric groups
Historical reporting functions correctly	✅ Daily/weekly/monthly aggregations pass
Dashboard summaries are available	✅ /analytics/dashboard returns full summary
Reports can be exported	✅ CSV and JSON exports tested
Performance targets are achieved	✅ p95 under 250ms with Redis caching
Monitoring metrics are exposed	✅ Latency, cache, and export metrics emitted
Unit and integration tests pass	✅ 68/68 tests passing

Closes #292