feat(admin): follow presets on mltext fields per locale

- formState: changedLocales and presetUpdates hold the preset-follow rules
  for text and mltext pairs
- FormView applies presetUpdates on create, tracks per-locale hand edits of
  ML fields and follows the active ML locale
- rebuilt modules/boardwalk/dist

admin/tests/form/formState.test.ts

@@ -1,5 +1,6 @@
 import { afterEach, describe, expect, it } from 'vitest'
 import {
+  changedLocales,
   contextAllows,
   DEFAULT_TAB,
   editablePayload,
@@ -8,12 +9,14 @@ import {
   initialValues,
   mergeMLValue,
   panelDomId,
+  presetUpdates,
   presetValue,
   snapshot,
   tabDomId,
   tabOf,
 } from '../../src/components/form/formState'
 import { extensionFormSchemaFixture, formField, formSchemaFixture, rosterFormSchemaFixture } from '../fixtures/typed'
+import type { FormField } from '../../src/api/types'
 
 afterEach(() => {
   document.body.innerHTML = ''
@@ -180,6 +183,76 @@ describe('preset values (D-27 G7)', () => {
   })
 })
 
+describe('presets on mltext fields', () => {
+  function presetFields(sourceType: string, targetType: string, presetType = 'slug'): FormField[] {
+    const source = formField('name')
+    source.type = sourceType
+    const target = formField('name')
+    target.name = 'slug'
+    target.type = targetType
+    target.preset = { field: 'name', type: presetType }
+    return [source, target]
+  }
+  const never = () => false
+
+  it('lists the locales whose text changed', () => {
+    expect(changedLocales({ en: '', pl: '' }, { en: 'A', pl: '' })).toEqual(['en'])
+    expect(changedLocales({ en: 'A', pl: 'B' }, { en: 'A', pl: 'B' })).toEqual([])
+    expect(changedLocales({ en: '' }, { en: '', pl: 'B' })).toEqual(['pl'])
+    expect(changedLocales({ en: 'A', pl: '' }, { en: 'A' })).toEqual([])
+    expect(changedLocales(undefined, { en: 'A' })).toEqual(['en'])
+    expect(changedLocales('text', { en: 'A', pl: '' })).toEqual(['en'])
+  })
+
+  it('keeps text -> text as before, and leaves an edited target out', () => {
+    const fields = presetFields('text', 'text')
+    expect(presetUpdates(fields, 'name', '', 'Hello World', {}, 'en', never)).toEqual({ slug: 'hello-world' })
+    expect(presetUpdates(fields, 'name', '', 'Hello World', {}, 'en', (target) => target === 'slug')).toEqual({})
+    expect(presetUpdates(fields, 'slug', '', 'x', {}, 'en', never)).toEqual({})
+  })
+
+  it('follows ML -> ML per locale and stops only an edited locale', () => {
+    const fields = presetFields('mltext', 'mltext')
+    const values = { name: { en: '', pl: '' }, slug: { en: '', pl: 'kept' } }
+    expect(presetUpdates(fields, 'name', { en: '', pl: '' }, { en: 'Hello World', pl: '' }, values, 'en', never)).toEqual({
+      slug: { en: 'hello-world', pl: 'kept' },
+    })
+    const later = { name: { en: 'Hello World', pl: '' }, slug: { en: 'hello-world', pl: '' } }
+    expect(presetUpdates(fields, 'name', later.name, { en: 'Hello World', pl: 'Witaj Świecie' }, later, 'pl', never)).toEqual({
+      slug: { en: 'hello-world', pl: 'witaj-wiecie' },
+    })
+    const plEdited = (target: string, locale?: string) => target === 'slug' && locale === 'pl'
+    expect(presetUpdates(fields, 'name', later.name, { en: 'Hello World', pl: 'Witaj' }, later, 'pl', plEdited)).toEqual({})
+    expect(presetUpdates(fields, 'name', later.name, { en: 'Other', pl: '' }, later, 'pl', plEdited)).toEqual({
+      slug: { en: 'other', pl: '' },
+    })
+    const exact = presetFields('mltext', 'mltext', 'exact')
+    expect(presetUpdates(exact, 'name', {}, { en: 'Hello World' }, {}, 'en', never)).toEqual({ slug: { en: 'Hello World' } })
+    expect(presetUpdates(fields, 'name', { en: 'A' }, { en: 'A' }, values, 'en', never)).toEqual({})
+  })
+
+  it('drives a text target from the ML source active locale', () => {
+    const fields = presetFields('mltext', 'text')
+    expect(presetUpdates(fields, 'name', {}, { en: 'Hello World', pl: 'Witaj' }, {}, 'en', never)).toEqual({ slug: 'hello-world' })
+    expect(presetUpdates(fields, 'name', {}, { en: 'Hello World', pl: 'Witaj' }, {}, 'pl', never)).toEqual({ slug: 'witaj' })
+    expect(presetUpdates(fields, 'name', {}, { en: 'Hello World' }, {}, 'de', never)).toEqual({ slug: '' })
+    expect(presetUpdates(fields, 'name', {}, { en: 'Hello World' }, {}, 'en', (target) => target === 'slug')).toEqual({})
+  })
+
+  it('writes only the active locale of an ML target from a text source', () => {
+    const fields = presetFields('text', 'mltext')
+    const values = { slug: { en: '', pl: 'kept' } }
+    expect(presetUpdates(fields, 'name', '', 'Hello World', values, 'en', never)).toEqual({ slug: { en: 'hello-world', pl: 'kept' } })
+    expect(presetUpdates(fields, 'name', '', 'Hello World', values, 'en', (target, locale) => target === 'slug' && locale === 'en')).toEqual({})
+  })
+
+  it('ignores a preset on any other target type', () => {
+    for (const type of ['mlmarkdown', 'checkbox', 'markdown']) {
+      expect(presetUpdates(presetFields('mltext', type), 'name', {}, { en: 'A' }, {}, 'en', never)).toEqual({})
+    }
+  })
+})
+
 describe('ML create seed and adopt merge', () => {
   it('seeds every enabled locale as an empty string', () => {
     const fields = [