Add Contract Renewal Workflow

[AliiiBenn]

Description

Currently, there's no automated workflow for contract renewals. Users must manually track when contracts are ending and create new ones.

Requirements

1. Automatic Contract End Alerts:

   • Already have basic alerts in settings
   • Make them more prominent for contract endings

2. Renewal Workflow:

   • When contract is near end, show "Renew" action
   • One-click to create new contract with:
     • Same employee, position, location
     • New start date (day after old end)
     • Copy other fields optionally

3. Contract History:

   • Show all contracts for an employee
   • This is part of Employee Detail (issue Add Employee Detail Page #95)

Acceptance Criteria

• Alerts for contracts near expiration are more visible
• Can renew contract with one click
• New contract pre-fills from old one

Priority

Medium - saves time on manual work