Implement Alert History Search

[Mosas2000]

## Description

Provide search and filtering over historical alerts so operators can investigate prior incidents quickly.

## Requirements and context

- Time range filters

• Severity filters

• Source filters

• Full-text search

• Pagination

• Export support

  Suggested execution

  Fork the repo and create a branch

  git checkout -b feature/backend-alert-history

  Implement changes

  • Create alert history search service

• Expose search API endpoints

• Add filtering and pagination

• Document alert history queries

  Example commit message

  feat: implement alert history search

  Guidelines

  • Assignment required before starting
  • PR must include a closing reference to this issue
  • Include screenshots or examples where applicable
  • Timeframe: 72 hours