regen: content/docs/references/system/email-template.mdx from the merged tree (os-regen-merge step 3)

Main's side of the generated reference, re-derived from the merged
email-template.zod.ts header (the registry flag cited as
allowEnvironmentOverlay). Discharges the merge commit's deferral.

Claude-Session: https://claude.ai/code/session_01KNKBCRDJCu5tGy3TEbvtrF
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

content/docs/references/system/email-template.mdx

@@ -9,10 +9,13 @@ description: "Declarative template definition consumed by IEmailService.sendTemp
 Email Template Metadata Protocol
 
 Declarative template definition consumed by `IEmailService.sendTemplate()`
-to render outbound mail. Persisted as rows of `sys_email_template` so
-administrators can author/edit/translate templates in Studio without
-shipping code, and an environment can overlay the packaged defaults
-(`allowEnvironmentOverlay: true` in the metadata registry).
+to render outbound mail. Read from the metadata registry by
+`(name, locale)` — the environment's item over each code package's
+declaration, the built-in auth templates included — so administrators can
+author/edit/translate templates in Studio without shipping code, and a
+Studio save overrides a built-in default at environment level
+(`allowEnvironmentOverlay: true` in the metadata registry). No
+`sys_email_template` row is read or written on the way.
 
 Aligned with Salesforce `EmailTemplate` and ServiceNow
 `sysevent_email_action` conventions: a single named template is