feat(18.1-01): task 2 taglist string mode, customTags and all save sites

- string mode: split on the separator (comma or whitespace), normalised,
  stored joined by a comma or one space; null stores an empty string
- customTags false refuses a tag outside options (taglist.not_allowed)
- taglist checked and hydrated on relation forms and settings forms;
  settings bind taglist columns; required checked on the tags
- admin: TaglistField string mode and closed option lists, preview renders
  the tags read-only as a comma-separated list; rebuilt dist
- docs: Taglist section covers both modes, separator and customTags

admin/tests/form/TaglistField.test.ts

@@ -5,6 +5,7 @@ import { enableAutoUnmount, mount, type VueWrapper } from '@vue/test-utils'
 import { nextTick } from 'vue'
 import type { FormField } from '../../src/api/types'
 import { setBundle } from '../../src/app/i18n'
+import PreviewField from '../../src/components/form/PreviewField.vue'
 import TaglistField from '../../src/components/form/fields/TaglistField.vue'
 import { langFixture } from '../fixtures/typed'
 import { resetState } from '../helpers'
@@ -115,4 +116,39 @@ describe('TaglistField', () => {
     expect(wrapper.find('b').exists()).toBe(false)
     expect(chips(wrapper)).toEqual(['<b>bold</b>'])
   })
+
+  it('splits and joins a string-mode value on its space separator', async () => {
+    const wrapper = mountField({ modelValue: 'x y', field: { mode: 'string', separator: 'space', options: [] } })
+    expect(chips(wrapper)).toEqual(['x', 'y'])
+    await type(wrapper, 'z ')
+    expect(emitted(wrapper)).toEqual(['x y z'])
+  })
+
+  it('joins a string-mode value with a comma by default', async () => {
+    const wrapper = mountField({ modelValue: 'a,b', field: { mode: 'string', separator: 'comma' } })
+    expect(chips(wrapper)).toEqual(['a', 'b'])
+    await type(wrapper, 'c')
+    await input(wrapper).trigger('keydown', { key: 'Enter' })
+    expect(emitted(wrapper)).toEqual(['a,b,c'])
+  })
+
+  it('refuses a tag outside the options when customTags is false', async () => {
+    const wrapper = mountField({ modelValue: [], field: { customTags: false } })
+    await type(wrapper, 'delta')
+    await input(wrapper).trigger('keydown', { key: 'Enter' })
+    expect(emitted(wrapper)).toEqual([])
+    await type(wrapper, 'beta')
+    await input(wrapper).trigger('keydown', { key: 'Enter' })
+    expect(emitted(wrapper)).toEqual([['beta']])
+  })
+
+  it('renders the tags joined as text on the preview screen', () => {
+    const wrapper = mount(PreviewField, {
+      props: { field: taglistField(), value: ['alpha', '<i>beta</i>'] },
+      attachTo: document.body,
+    })
+    expect(wrapper.find('[data-taglist-readonly]').text()).toBe('alpha, <i>beta</i>')
+    expect(wrapper.find('i').exists()).toBe(false)
+    expect(wrapper.find('input').exists()).toBe(false)
+  })
 })