Create Time Conversion Utilities

[alejandro-runner]

Scope

Create helper functions for time format conversion between ISO8601 and Unix timestamps with IANA timezone identifiers.

Tasks

• Create utility functions to convert ISO8601 ↔ Unix timestamp + IANA timezone
• Handle timezone detection and conversion
• Add comprehensive tests for time conversion utilities

Files to Create

• client/src/lib/reservationTimeUtils.ts (new)
• client/src/lib/reservationTimeUtils.test.ts (new)

Requirements

• Convert ISO8601 strings (e.g., "2025-10-20T19:00:00-07:00") to Unix timestamp + IANA timezone (e.g., 1729458000 + "America/Los_Angeles")
• Convert Unix timestamp + IANA timezone back to ISO8601 for display
• Handle timezone conversions properly