First Wave 2 (safe refactor) slice. Move the read-only stats/overview aggregation
out of the 3.3k-line JobApplicationsController into a dedicated, injectable
AnalyticsService, and lift its response DTOs (JobStats, FunnelStagePoint,
ResponseRatePoint, CompanyActivityPoint, AnalyticsOverviewDto) into
Models/AnalyticsDtos.cs.
- GetStats: ~44 lines -> 3 (delegates to AnalyticsService.GetStatsAsync).
- GetAnalyticsOverview: ~82 lines -> 3 (delegates to GetAnalyticsOverviewAsync).
- Registered AddScoped<AnalyticsService>(); controller keeps an optional ctor
param with a `?? new AnalyticsService(db)` fallback so the 6 test sites that
construct the controller directly keep compiling.
- Logic is byte-identical (same tenant-scoped context, same projections) so
behaviour is preserved.
Backend suite: 92/92 green.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>