refactor: standardize UTC date handling across backend

[starboytiimz]

Closes #153

Summary

Standardizes date/time handling across the backend to UTC, fixing one genuine timezone-boundary bug and consolidating date construction behind shared utils for consistency.

Changes

• src/utils/dateUtils.ts (new) — nowUTC(), toUTC(), toISOUTC() helpers
• src/models/DriverProfile.ts (modified) — vehicle year validation used new Date().getFullYear(), which reads the server's local time and could misvalidate near a UTC day/year boundary depending on server locale. Now uses nowUTC().getUTCFullYear().
• src/services/escrowService.ts, src/services/idempotency.service.ts, src/sockets/sync.service.ts, src/sockets/location.service.ts (modified) — replaced direct new Date()/new Date(x) calls with nowUTC()/toUTC() for consistency. Note: these were already timezone-safe (no local-time accessor methods were in use), so this is a non-behavioral consistency change, not a bug fix.

Audit

Searched the full src/ tree for local-timezone-dependent accessor usage (getFullYear, getHours, getDate, getDay, getMonth, toLocaleDateString, toLocaleString) outside the files above. No further instances found.

Architecture

• Pure refactor, no new endpoints, no schema changes
• No new dependencies added

Security / Rollback

• No new attack surface, date handling only
• Rollback: revert this branch's commits; MongoDB already stores Date as UTC internally, no data migration involved.

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[starboytiimz]

@Tybravo please approve workflow for the two pr's created. Thanks

[Tybravo]

@starboytiimz
Thanks for contributing