Restructure & Improve TZDB Processing

[vamsii777]

Overview

This PR introduces significant improvements to timezone handling.

Key Changes

• Dual-Source Timezone Parsing: The library now supports dual-source timezone parsing, utilizing both zonenow.tab and zone1970.tab files for timezone information.
• Type Differentiation: The library has been enhanced to differentiate between current and historical timezones, facilitating more accurate timezone handling.
• Improved PKL Schema Generation: The PKL schema generation process has been refined, incorporating improved type handling to ensure data integrity.

⚠️ Breaking Changes

• Removed Linux test workflow (will be reintroduced in future release)
• Modified timezone identifier structure to support both current and historical zones

Testing

• ❌ All macOS tests passing
• ✅ Timezone generation verified with both current and historical data
• ✅ TZDB update automation tested with sample data

Follow-up Tasks

• Reintroduce Linux testing in future release
• Consider adding timezone metadata API