Evidence hub retention

[HarshP4585]

Describe your changes

• Evidence hub retention policy and expiry

Write your issue number after "Fixes "

Fixes #4587

Please ensure all items are checked off before requesting a review:

• I deployed the code locally.
• I have performed a self-review of my code.
• I have included the issue # in the PR.
• I have labelled the PR correctly.
• The issue I am working on is assigned to me.
• I have avoided using hardcoded values to ensure scalability and maintain consistency across the application.
• I have ensured that font sizes, color choices, and other UI elements are referenced from the theme.
• My pull request is focused and addresses a single, specific feature.
• If there are UI changes, I have attached a screenshot or video to this PR.
• If I added or modified an API endpoint, the change is reflected in the generated OpenAPI spec (npm run generate:swagger).
• If the endpoint requires authentication, it uses authenticateJWT and the generated spec declares bearerAuth security.
• I ran npm run check:api-drift and committed the regenerated swagger.yaml and endpoints.ts.
• If this PR adds or modifies an organization-scoped table, the tenant isolation registry and test matrix are updated. See the tenant isolation runbook for details.

[github-actions]

✅ Coverage Gate Passed

All coverage thresholds are met.

[gorkem-bwl]

Screenshots look good.

[MuhammadKhalilzadeh]

Let's fix the CI check errors @HarshP4585

[MuhammadKhalilzadeh]

There's a little conflict here @HarshP4585 , feel free to merge after fix

[MuhammadKhalilzadeh]

Hello @HarshP4585
Let's have the conflicts resolve as soon as possible, please. This PR is staying for a while now