feat(14.2.1-05): cover mlmarkdown, child adopt, and regen admin artifacts

MLMarkdownField and relation-child forms share the enabled-locale
inject and adopt merge; OpenAPI, types, docs, and boardwalk dist match.

Co-authored-by: Cursor <cursoragent@cursor.com>

docs/backend/admin-controllers.md

@@ -202,7 +202,7 @@ Every controller gets the same routes, relative to `<prefix>/api/v1/{vendor}/{pl
 
 The cabana README lists the full route table, including relation, options, widget, toolbar and partial routes. Every response uses one JSON envelope (`cabana.Envelope`), and a validation failure is a 422 `validation_failed` error with messages per field.
 
-Request parameters never reach SQL directly: search, sort and filters apply only to declared columns, and a write passes only the form's writable fields, filled through `lagoon.Fill` and validated through `lagoon.Validate` in a transaction. A `mltext` or `mlmarkdown` field arrives as a nested locale map: cabana lifts it before `cabana.ProjectWritableFields` drops nested values, writes the default locale as the host scalar, and calls a published `cabana.TranslationWriter` for the other locales inside the same permissioned save transaction. There is no separate translate-write route; see [Markdown and multilingual fields](forms.md#markdown-and-multilingual-fields).
+Request parameters never reach SQL directly: search, sort and filters apply only to declared columns, and a write passes only the form's writable fields, filled through `lagoon.Fill` and validated through `lagoon.Validate` in a transaction. A `mltext` or `mlmarkdown` field arrives as a nested locale map: cabana lifts it before `cabana.ProjectWritableFields` drops nested values, writes the default locale as the host scalar, and calls a published `cabana.TranslationWriter` for the other locales inside the same permissioned save transaction. The show and save record payload then carries that nested map for every enabled locale (`hydrateMLRecord` via `TranslationWriter.TranslatedExact`; missing non-default codes stay empty). There is no separate translate-write or translate-read route; see [Markdown and multilingual fields](forms.md#markdown-and-multilingual-fields).
 
 ## Hooks
 

docs/backend/forms.md

@@ -325,7 +325,7 @@ func (MembersController) AdminSetPermissionValues(_ context.Context, field strin
 
 `type: markdown` edits markdown source on a host text column. The admin SPA shows a source editor and may preview HTML from `cabana.RenderMarkdown`, which uses the pinned goldmark engine without unsafe HTML. Output that still contains a script or iframe tag, an event handler, or a javascript, vbscript or data URL is refused, so translated raw HTML cannot become executable preview content.
 
-`type: mltext` and `type: mlmarkdown` reuse the ordinary text and markdown editors with a locale selector. `mlmarkdown` composes the markdown control rather than a second parser. Each ML field shows its own selector; changing one selector changes every ML control on the form. Copy-from-locale fills the active locale from another code already in the value.
+`type: mltext` and `type: mlmarkdown` reuse the ordinary text and markdown editors with a locale selector. `mlmarkdown` composes the markdown control rather than a second parser. Each ML field shows its own selector; changing one selector changes every ML control on the form. Copy-from-locale fills the active locale from another code already in the value. Selector options come from `cabana.FormMeta.EnabledLocales` on the form schema (filled from `cabana.TranslationWriter.EnabledLocales` after Lookup; `FormSchema.Localize` stays cache-only). Create seeds `{[code]: ""}` for every enabled code. A GET or save of a host scalar is merged onto that seed so sibling locales are not dropped.
 
 The save body sends every locale as a JSON object of code to string. Extra YAML keys are not accepted: the types reuse `label`, `comment`, `span`, `size`, `required`, `tab` and `context`. An unknown type such as `mlunknown` stops the start-up.
 
@@ -345,7 +345,7 @@ fields:
         tab: acme.blog::lang.posts.tab_content
 ```
 
-A save of `{ "title": { "en": "Hello", "pl": "Witaj" } }` lifts the nested map before `cabana.ProjectWritableFields` drops nested values. The default locale fills the host column; other locales are written through a published `cabana.TranslationWriter` after the host row has a primary key, still inside the controller's permissioned save transaction. The default locale is not duplicated into the translation store. A non-string value, an undeclared locale, a missing default locale, or a nested map on a field that is not declared multilingual is a 422 on that field. Generic nested objects on other field types are still dropped. Cabana never imports a translate plugin and never exposes a public translate-write route: if no writer is published, a nested ML map is a 422.
+A save of `{ "title": { "en": "Hello", "pl": "Witaj" } }` lifts the nested map before `cabana.ProjectWritableFields` drops nested values. The default locale fills the host column; other locales are written through a published `cabana.TranslationWriter` after the host row has a primary key, still inside the controller's permissioned save transaction. The default locale is not duplicated into the translation store. Show and save then run `hydrateMLRecord`: each declared ML field in the record payload is a map of every enabled locale (default from the host column, others from `TranslationWriter.TranslatedExact`; a missing non-default code is an empty string, never D-11 fallback). A non-string value, an undeclared locale, a missing default locale, or a nested map on a field that is not declared multilingual is a 422 on that field. Generic nested objects on other field types are still dropped. Cabana never imports a translate plugin and never exposes a public translate-write or translate-read route: if no writer is published, a nested ML map is a 422.
 
 ## What a save may write