fix(streak): add .filter(Boolean) guards to aggregate/calculate calendars

[hardik-bhalekar]

Summary

Adds defensive .filter(Boolean) guards to every array iteration over calendar.weeks and contributionDays in the data-processing pipeline, preventing TypeError: Cannot read properties of null crashes when the GitHub GraphQL API returns sparse or null calendar records.

Problem

The GitHub Contributions GraphQL API occasionally returns null entries inside the weeks array or contributionDays sub-arrays — especially for newly created accounts, accounts with gaps in activity, or during API degradation. The existing code uses .flatMap() and .forEach() on these arrays without null guards, causing runtime crashes that surface as 500 errors on the streak card endpoint.

Changes

lib/github.ts — fetchContributionsUncached()

• Added .filter(Boolean) after (calendar.weeks || []) before .map()
• Added .filter(Boolean) after contributionDays array before .map()

lib/calculate.ts — Multiple functions

Function	Guard Added
calculateStreak()	.filter(Boolean) on weeks and contributionDays; added !d.date null-check
calculateMonthlyStats()	.filter(Boolean) on weeks and contributionDays
aggregateCalendars()	.filter(Boolean) on all 3 weeks/contributionDays iteration loops
calculateWrappedStats()	.filter(Boolean) on weeks and contributionDays
normalizeCalendarToTimezone()	.filter(Boolean) on calendar.weeks and contributionDays

Why .filter(Boolean)

This is the idiomatic JavaScript/TypeScript pattern for stripping null, undefined, 0, and "" from arrays in a single pass. It's safe here because contribution day objects are always truthy when present, and falsy entries are always invalid API artifacts.

Testing

• npx tsc --noEmit passes with zero errors
• Null/undefined entries in weeks or contributionDays are safely skipped
• Valid contribution data is processed identically to before

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[github-actions]

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