Add dynamic Privacy Policy URL configuration

[heysamtexas]

Description

Allow admins to configure Privacy Policy URL dynamically through Django admin interface.

Current State

Privacy policy links are likely hardcoded or missing.

Proposed Implementation

Add field to SiteConfiguration model:

• privacy_policy_url - URLField for privacy policy link
• privacy_policy_required - BooleanField for mandatory acceptance

Benefits

• Quick updates for privacy compliance (GDPR, CCPA)
• No developer involvement for legal updates
• Consistent privacy policy links across site

Acceptance Criteria

• Add privacy policy URL field to SiteConfiguration
• Display link in footer, registration, and account settings
• Optional: Privacy policy acceptance requirement
• URL validation
• Test all link placements

Labels: enhancement, ui/ux, legal, privacy
Priority: Medium