feat(timezones): improve timezone support

[JeanMeijer]

Description

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Type of Change

• Bug fix
• New feature
• Breaking change
• UI/UX update
• Docs update
• Refactor / Cleanup

Related Areas

• Authentication
• Calendar UI
• Data/API
• Docs

Testing

• Manual testing performed
• Cross-browser testing (if UI changes)
• Mobile responsiveness verified (if UI changes)

Checklist

• I’ve read the CONTRIBUTING guide
• My code works and is understandable and follows the project's style guidelines
• I have performed a self-review of my code
• I have commented my code, particularly in complex areas
• I have updated the documentation
• Any dependent changes are merged and published

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Summary by cubic

Improves timezone support and display accuracy across the app. Calendar header and timezone lists now use a DST-aware dataset for correct names, abbreviations, and UTC offsets on any date.

• New Features

  • Ships @repo/timezones with canonical/linked zones, city data, standard offset periods, and DST periods.
  • Uses DST-aware abbreviations and names with Intl fallback when data is missing.
  • Expands Windows-to-IANA mapping for Microsoft Calendar (adds UTC, US Eastern, Haiti, Cuba, Paraguay, and more).

• Refactors

  • Replaced use-timezone-info.ts with use-timezone.ts and centralized formatting in getDisplayValue.
  • Removed runtime reliance on @vvo/tzdb; now use @repo/timezones + Intl.
  • Updated calendar store hook to pull labels from getDisplayValue.
  • Added @repo/timezones to apps/web dependencies and lockfile.

^{Written for commit 466bd8f. Summary will update on new commits.}

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Project	Deployment	Actions	Updated (UTC)
analog	Ready	Preview, Comment	Jul 16, 2026 4:40pm

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