Feature: Privacy Consent Center and Portable Data Export

Summary

Add a privacy and data portability center where users can review what Moodify stores, control consent for optional history-based personalization, and export their account data in a portable format.

Problem / Opportunity

Moodify stores mood history, listening history, and saved recommendations for authenticated users. The app already includes profile deletion and list-clearing controls, but users do not have a single privacy surface that explains stored data, separates optional personalization consent from required account data, or lets them export their own data.

Because Moodify works with sensitive emotional signals, a transparent consent and export workflow is a substantial product capability, not a cosmetic settings change.

Proposed Feature

Build a privacy center for web and mobile that includes:

• A data inventory explaining account fields, mood history, listening history, saved recommendations, and recommendation feedback if implemented later.
• Per-user consent toggles for optional personalization inputs, such as using mood history in recommendation requests or storing listening-history events.
• A data export flow that produces a JSON file containing profile metadata, mood history, listening history, saved recommendations, and consent settings.
• A server-side export endpoint that requires authentication and returns only the current user's data.
• Clear status states for export generation, errors, and empty histories.
• Audit-friendly timestamps for consent changes.

Scope

• Backend consent fields and export serialization.
• Authenticated API endpoints for reading/updating privacy preferences and downloading/exporting user data.
• Web Profile/Settings privacy center UI.
• Mobile Settings privacy center UI.
• Recommendation request behavior that respects personalization consent.
• Tests for authorization, export schema, consent persistence, and personalization opt-out behavior.

Acceptance Criteria

• Authenticated users can view a privacy center that summarizes stored Moodify data categories.
• Users can opt out of mood-history personalization without deleting existing mood history.
• Users can opt out of listening-history storage so future track opens are not persisted.
• Consent changes are persisted with an updated timestamp.
• Users can export their data as JSON from an authenticated endpoint.
• The export includes profile metadata, mood history, listening history, saved recommendations, and consent settings.
• Export endpoints reject unauthenticated requests and never allow exporting another user's data.
• Web and mobile clients honor opt-out settings when saving history or passing history into recommendations.
• Tests cover export authorization, export shape, consent updates, and client opt-out behavior.

Non-Goals

• Legal compliance certification or policy rewriting.
• Admin access to user exports.
• Bulk export for all users.
• Replacing the existing account deletion workflow.

Dependencies / Risks

• Needs a stable export schema so future clients or tools can consume the data reliably.
• Consent behavior must be enforced client-side and server-side where possible, not only hidden in UI.
• Existing users will need default consent values that preserve current behavior until changed.

Open Questions

• Should export generation be synchronous JSON for the current data size, or an async job for future scalability?
• Should exported recommendation records include full track metadata or only normalized identifiers and display fields?
• Should consent defaults differ between new users and existing users?