fix(locale): correct meridiem boundary in all Arabic locales

[mahmoodhamdi]

What

Fixed the meridiem (AM/PM) boundary condition in all 8 Arabic locale files (ar, ar-sa, ar-ma, ar-dz, ar-iq, ar-kw, ar-ly, ar-tn).

Why

I use day.js with Arabic locale in my projects and noticed that at exactly 12:00 noon, the meridiem returns ص (AM) instead of م (PM).

The issue is that all Arabic locales use hour > 12 instead of hour >= 12:

// Before (incorrect): hour 12 → ص (AM) ❌
meridiem: hour => (hour > 12 ? 'م' : 'ص')

// After (correct): hour 12 → م (PM) ✅
meridiem: hour => (hour >= 12 ? 'م' : 'ص')

This is inconsistent with:

• The core default meridiem in src/index.js which uses hour < 12 (meaning >= 12 is PM)
• Other locales like ja, ko, br, ku which all use hour < 12

In the 24-hour system, hour 12 is noon and should be PM (مساءً), not AM (صباحاً).

Changes

• src/locale/ar.js — > 12 → >= 12
• src/locale/ar-sa.js — > 12 → >= 12
• src/locale/ar-ma.js — > 12 → >= 12
• src/locale/ar-dz.js — > 12 → >= 12
• src/locale/ar-iq.js — > 12 → >= 12
• src/locale/ar-kw.js — > 12 → >= 12
• src/locale/ar-ly.js — > 12 → >= 12
• src/locale/ar-tn.js — > 12 → >= 12
• test/locale/ar.test.js — fixed meridiem test assertion to match corrected behavior

Testing

• All 93 test suites pass (773 tests)
• npm run lint passes with no errors