feat(schemas): add new email templates table

[simeng-li]

Summary

In the previous implementation, we only supported one copy of the email templates configured under the email connector's settings. This becomes a limitation for some of our customers who require i18n support for their email templates. Users from different regions may receive emails in different languages, just like our SIE i18n phrases. We need to support i18n templates to meet the requirements

In addition to the current default email templates stored in connector configs, we need to add an extra global setting to allow users to configure multiple email templates for different languages. This PR introduces the new email_templates table.

This table will be used to globally maintain custom email templates with i18n support for developers. We will detect the user's language preference and locate the corresponding email template using the following priority:

• p0: If the language auto-detection is enabled in SIE, we will use the user's browser language preference to locate the email template. (e.g. Accept-Language: en-US)
• p1: If the language auto-detection is enabled in SIE, but the API request does not contain the Accept-Language header (e.g. Management API triggered email sending flow), use the locale value stored in the user's profile data.
• p2: If the language auto-detection is enabled in SIE, but the user's profile does not have the locale value, use the default language in SIE.
• p3: If the language auto-detection is disabled in SIE, use the default language in SIE.
• fallback: If the email template for the detected language is not found, use the default email template from the connector settings. (Current behavior)

Note

These new i18n email templates will be used globally regardless of the email connector.
We use a shared schema type to define all the email template details. The connector-level template key mapping logic is needed based on different email connectors' interface definitions.
The following email connectors do not support custom email templates. i18n and template customization will be managed by the email provider:

• Postmark
• HTML Email
• Logto cloud email service. (Read-only i18n email templates will be provided by Logto cloud service)

Testing

N/A

Checklist

• .changeset
• unit tests
• integration tests
• necessary TSDoc comments

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Total Size Diff 📈 +3.3 KB

Diff by File

Name	Diff
packages/schemas/alterations/next-1738828268-add-email-templates-table.ts	📈 +1.27 KB
packages/schemas/src/foundations/jsonb-types/email-templates.ts	📈 +1.29 KB
packages/schemas/src/foundations/jsonb-types/index.ts	📈 +38 Bytes
packages/schemas/tables/email_templates.sql	📈 +725 Bytes