Add comprehensive implementation plan for Transaction Trends analytics feature

[Copilot]

Planning document for a new Transaction Trends view that analyzes user spending patterns across all accounts, providing insights into transaction types, merchant categories, and account-level comparisons.

Deliverables

TRANSACTION_TRENDS_IMPLEMENTATION_PLAN.md

• Complete technical specification with architecture, data structures, and API design
• 3-phase implementation roadmap (Foundation → Core Analytics → Polish)
• 12 discrete tasks with complexity estimates and dependencies
• Category detection patterns and metric calculations
• Risk analysis, constraints, and future enhancement scope
• 6-8 hour timeline estimate

TRANSACTION_TRENDS_QUICK_REFERENCE.md

• Condensed implementation checklist for active development
• Code snippets for routes, views, and analysis functions
• Testing strategy and edge case coverage
• File modification map

Technical Approach

Route: GET /services/trends in existing services router
Analysis: Server-side aggregation using pure JavaScript (zero new dependencies)
View: EJS template following existing patterns (header/footer includes, .data-panel tables)
Data: Pattern-based merchant categorization from existing accounts.json transactions

Key Metrics Planned

• Overall: total transactions, debits/credits, net change, averages
• By Type: debit vs credit breakdown with percentages
• By Category: spending grouped by Food, Shopping, Income, Transfers, Other
• By Account: checking/savings/credit comparison
• Top Merchants: top 5 by total spending

Example Analysis Structure

router.get('/trends', (req, res) => {
  const trendData = {
    summary: { totalTransactions, totalDebits, totalCredits, netChange, avgTransaction },
    byType: { debits: { count, total, percentage }, credits: {...} },
    byCategory: [{ name: 'Food & Dining', count, total, percentage }, ...],
    byAccount: [{ name: 'Checking', count, total }, ...],
    topMerchants: [{ name: 'SHARP*EMPLOYER', count, total }, ...]
  };
  res.render('trends', { title: 'Transaction Trends', ...trendData });
});

Implementation follows existing services pattern (transfer/payment routes) with no breaking changes to current functionality.

Original prompt

plan implementation of a new view - transaction trends, that gives some information to user on the trends/patterns of their transactions

Note

Custom agent used: implementation-planner
Creates detailed implementation plans and technical specifications in markdown format

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