Add Dashboard Statistics Improvement Plan

[mnindrazaka]

Summary

This PR introduces a comprehensive planning document for enhancing the Dashboard with three new operational statistics features: date-range filtering for transaction totals, product/variant sales tracking, and material usage monitoring.

Changes

• Added DASHBOARD_STATISTICS_PLAN.md: A detailed specification document that outlines:
  • Current state of the Dashboard and identified gaps
  • Three core requirements: transaction totals, product/variant sales, and material usage statistics
  • Design decisions establishing patterns for date-range filtering, dashboard layout, and clean-architecture consistency
  • A phased implementation plan with 4 phases (0-3), each broken into independently reviewable PRs
  • Cross-cutting checklist for quality assurance across features
  • Resolved decisions confirmed with stakeholders (layout, metrics, units, transaction scope)

Implementation Approach

The plan follows the existing clean-architecture pattern (entity → repo iface → usecase → data → controller → handler → screen → component → app → page) to ensure consistency and testability. Each phase is sized for isolated review:

• Phase 0: Add date-range filtering to existing transaction statistics (BE + FE)
• Phase 1: Implement product/variant sales statistics with granularity toggle
• Phase 2: Generalize and expose material usage statistics for inventory planning
• Phase 3: Unify dashboard UX with shared controls and polish

The document establishes reusable patterns (date-range query params, optional filters, backwards compatibility) and clarifies data model relationships needed for each statistic.

https://claude.ai/code/session_01Run2v6qy5e7eQjrSKMqfZ3