docs(cabana): document preset on mltext fields

- schema_types.go and the form-schema swag description name text or mltext
- regenerated admin/openapi/admin.json and admin/src/api/schema.d.ts
- README and docs/backend/forms.md describe the per-locale rules

modules/cabana/README.md

@@ -25,7 +25,7 @@ Schema-driven admin backend that compiles WinterCMS-style YAML list, form, filte
 - Form-only fields: a controller implementing `pact.FormVirtualFields` lists fields of its `fields.yaml` that are not columns of the form. They are exempt from the column binding, never filled into the model and never part of a record response; the values an administrator submits reach the Form hooks through `cabana.VirtualFieldsFromContext`, only for fields whose `context` allows the operation, and a nested value is a 422 on the field. `type: password` is a masked field that must be listed this way, so a password is sent in a save body and never comes back. A controller implementing `pact.FormRules` supplies the validation rules per operation (`create` or `update`), which replace the model's `Rules()` for admin saves; a rule on a virtual field is checked against the submitted value, never against a model column of the same name. Neither is available on settings forms or relation forms.
 - Permission editor: a `type: permissioneditor` field with `mode: radio` (allow `1`, inherit, deny `-1`) or `mode: checkbox` (allow `1`) edits a record's permission set as a JSON object of code to integer. The controller implements `cabana.PermissionEditorProvider`: it returns the offered `cabana.PermissionOption` list per request (served on the field as `permissionOptions`, with `locked` for permissions the administrator may not change) and reads and stores the record's values, so the storage shape is the plugin's. A save answers 422 on the field for a value that is not an object of integers, a code that is not offered or a value outside the mode's set, and 403 `forbidden` when a locked code's value changes; stored codes that are not offered are kept. The widget fill contract is unchanged: a widget still writes scalar fields only.
 - Markdown and multilingual fields: `type: markdown` edits source on a host text column; `cabana.RenderMarkdown` turns that source into HTML with the pinned goldmark engine and no unsafe HTML, and leftover script or iframe tags, event handlers, or javascript, vbscript or data URLs are rejected; the admin form preview renders through it via POST `/markdown/preview`. `type: mltext` and `type: mlmarkdown` take a JSON object of locale code to string. The form schema's `cabana.FormMeta.EnabledLocales` lists every enabled code when a `cabana.TranslationWriter` is published; create seeds an empty string per code, and Show/save replace the host scalar with that map via `hydrateMLRecord` and `TranslationWriter.TranslatedExact` (missing non-default codes stay empty; D-11 fallback is not applied). A GET host string is merged onto the seed so sibling locales are not dropped. The default locale fills the host column; other locales reach a plugin-published `cabana.TranslationWriter` after the host row has a primary key, still inside the controller's permissioned save transaction. Relation-child create, update and show on `cabana.RelationService` use the same lift, apply and `hydrateMLRecord` path as controller save, still with no standalone translate-write route. An unknown field type, including an unknown `ml*` type, fails boot.
-- Preset fields: `preset` on a `type: text` field (a source field name, or a mapping with `field` and `type`, `slug` or `exact`) makes the field follow another text field of the same form on the create screen until the administrator edits it. The schema reports it as `preset` (`cabana.FieldPreset`); the server does not fill the field.
+- Preset fields: `preset` on a `type: text` or `type: mltext` field (a source field name, or a mapping with `field` and `type`, `slug` or `exact`) makes the field follow another text or mltext field of the same form on the create screen until the administrator edits it, per locale for an mltext pair. The schema reports it as `preset` (`cabana.FieldPreset`); the server does not fill the field.
 - Server-rendered partials: `headerPartial: <name>` in `config_list.yaml` (a strip above the list) and `type: partial` with `path: <name>` in `fields.yaml` render the template `{ConfigDir}/_<name>.htm` with `html/template` against a view model from the controller's `pact.AdminPartialData`. The result reaches the SPA as an allowlisted node tree, never as an HTML string. A missing or unparsable template, a free-form path or a controller without `pact.AdminPartialData` fails boot.
 - Date pickers: a `type: datepicker` field in `fields.yaml` edits a date (`mode: date`, a `lagoon.Date` column), a date and time (`mode: datetime`, the default, a `time.Time` column stored in UTC) or a time of day (`mode: time`, a `lagoon.TimeOfDay` column); pointers to the three types make the value optional. It accepts WinterCMS's `mode`, `format` (a PHP `date()` format, served also as `displayFormat` in the SPA's tokens), `minDate`, `maxDate`, `yearRange`, `firstDay`, `twelveHour` and `ignoreTimezone`; any other key, a format letter with no equivalent, bounds on `mode: time`, `ignoreTimezone` outside `mode: datetime` or a column whose Go type does not match the mode fails boot. The save rechecks `minDate` and `maxDate` on the calendar date and answers 422 on the field. List columns take `type: date` and `type: time` for these columns; when `type` is omitted, a `time.Time` column is compiled as `datetime`, a `lagoon.Date` column as `date` and a `lagoon.TimeOfDay` column as `time`. A struct column that implements `sql.Scanner` or `driver.Valuer` is never taken for a relation.
 - File uploads: a `type: fileupload` field in `fields.yaml` edits an attachOne or attachMany relation the record model declares through `attach.HasRelations` (its `AttachRelations` method) next to `attach.Owner`. The field accepts WinterCMS's `mode` (`image` or `file`), `fileTypes`, `mimeTypes`, `maxFilesize` (megabytes), `maxFiles` (attachMany only), `imageWidth`, `imageHeight`, `thumbOptions` (only `mode`: `auto`, `exact`, `crop` or `fit`), `useCaption` and `prompt`; any other key, an image-mode file type outside jpg, jpeg, png, gif and webp, a name that is not a declared relation or a `maxFilesize` whose file plus 64 KiB of multipart framing exceeds `http.body_limits.upload_bytes` fails boot. Uploads and removals are deferred, as in WinterCMS: the SPA sends a random form session key in the `X-Session-Key` header (`cabana.SessionKeyHeader`) with every file call and with the save, the server keeps the pending work in `deferred_bindings` against that key and the signed-in administrator, and the record's next create or update save applies it inside its transaction. A retry of the same upload may send `X-Upload-Id` so the server returns the already stored file. A save that fails with 422 keeps the pending uploads; another administrator's key matches nothing. The upload route caps the request body at the smaller of `http.body_limits.upload_bytes` and `maxFilesize` plus 64 KiB and answers 413 `payload_too_large` past it; the size, type and image checks run on the server (through `attach.Store`) and answer 422 on the field. A file list (`cabana.FileItem`) carries `url` and `thumb_url` only for a public relation.
@@ -222,7 +222,7 @@ func (p *Plugin) AdminFS() fs.FS { return adminFS }
 | `cabana.TranslationWriter.TranslatedExact` | Returns the stored value for a field in a locale without D-11 fallback; `ok` is false when the non-default key is missing. The default locale still reads the host column. |
 | `hydrateMLRecord` | Replaces host scalars of declared `mltext`/`mlmarkdown` fields on a Show/save record — host CRUD and relation-child create, update and show — with a locale map for every enabled code. Not used from list row projection. |
 | `cabana.RenderMarkdown` | Converts markdown source to HTML with the pinned goldmark engine without unsafe HTML; leftover script or iframe tags, event handlers, or javascript, vbscript or data URLs are rejected. |
-| `cabana.FieldPreset` | A text field's `preset` in the form schema: the source field and the type, `slug` or `exact`. |
+| `cabana.FieldPreset` | A text or mltext field's `preset` in the form schema: the source field and the type, `slug` or `exact`. |
 | `cabana.WriteData` / `cabana.WriteError` / `cabana.WriteErrorDetails` | Write the admin success and error envelopes. |
 | `cabana.ValidationError` / `cabana.ListValidationError` | Field-level `validation_failed` errors. A `pact.AdminAction` may return a `cabana.ValidationError` to answer 422. |
 | `cabana.ForbiddenError` | A write controller code refuses: a hook or an action returns it and the route answers 403 `forbidden` with its localized `Message` and `Details`; the transaction is rolled back. |