Make email preference defaults and mandatory overrides consistent across onboarding and updates

[grantfox-oss]

Context

The email preference service in src/services/email-preference.service.ts has a clear preference model, but the default handling and mandatory overrides are split across multiple code paths. This can lead to inconsistent preferences for newly created users and for updates that modify only part of the preference payload.

Problem statement

Standardize how default preferences are created, merged, and enforced so that onboarding and later updates behave consistently and mandatory security notifications always remain deliverable.

Current behavior

• src/services/email-preference.service.ts builds default preferences in one place, but the merge logic for updates and the mandatory override behavior are partially embedded in the service methods.
• New users and existing users can hit slightly different code paths depending on whether preferences exist yet.

Required behavior

• Default preferences should be created and merged in a single, predictable way.
• Mandatory notification types should always bypass user preference opt-outs.
• Preference updates should preserve the expected defaults while honoring explicit user changes.

Constraints

• The change should preserve the current notification categories and API responses.
• Existing preference records should remain valid after the change.

Acceptance criteria

• Newly created users receive the expected default preference set.
• Mandatory notification types are still delivered even when the user disables related categories.
• Updating preferences merges correctly without dropping default categories.
• Unit tests cover defaults, overrides, and update merges.

Out of scope

• Reworking the notification taxonomy or introducing a new preferences UI.
• Changing the email delivery infrastructure.

Hints and references

• Review the shared EmailPreferenceCategories shape and the shouldSendEmail logic for the current precedence rules.

[Truphile]

Hi team, I’d love to take this on!

I am a software engineer focused on structural code quality, clean separations of concern, and deterministic error handling. I am ready to break down these requirements into a highly reliable, production-ready solution.

I will deliver:

Decoupled Architecture: Implement the core business logic using explicit boundaries, ensuring the solution remains modular, easy to audit, and free of hidden side effects.

Pipeline & Storage Sync: Cascade all necessary data-model updates smoothly across the API surface, background workers, and persistent data layers to maintain total state synchronization.

Component Resilience: Refactor or deploy intuitive user-facing elements that cleanly represent async transitions, edge-case states, and form validations.

Automated Regression Suite: Construct a matching matrix of unit and integration tests designed to aggressively exercise boundary conditions and ensure continuous CI pass marks.

Ready for assignment to drop a complete, highly polished PR immediately!