Use rolling 30-day window for annual projections instead of current month

[Copilot]

Annual projections calculated from current month data are unstable early in the month (e.g., projecting from 2 days of data on Feb 2nd). Changed to use a rolling 30-day window for consistent predictions throughout the month.

Changes

Backend (extension.ts)

• Added last30Days period to DetailedStats interface
• Modified calculateDetailedStats() to accumulate stats for sessions within last 30 days
• Updated file filtering boundary from lastMonthStart to last30DaysStart

Frontend (details/main.ts)

• Replaced projection formula: (monthValue / currentDay) * daysInYear → (last30DaysValue / 30) * 365.25
• Updated all projection displays (metrics, editor usage, model usage) to use stats.last30Days

// Before: volatile at month start
function calculateProjection(monthValue: number): number {
  const day = now.getDate();  // 1-2 days early in month
  return (monthValue / day) * daysInYear;
}

// After: stable 30-day rolling average
function calculateProjection(last30DaysValue: number): number {
  return (last30DaysValue / 30) * 365.25;
}

This provides stable projections regardless of calendar position while maintaining accurate year-over-year trending.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• update.code.visualstudio.com
  • Triggering command: /home/REDACTED/work/_temp/ghcca-node/node/bin/node node /home/REDACTED/work/github-copilot-token-usage/github-copilot-token-usage/node_modules/.bin/vscode-test (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

update all the prediction data to be using the last 30 days counters instead of the current month counters. that should give us better info during the beginning of the month

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