feat(10-03): tabs, toggles, relation fields, form lifecycle and settings pages

- FormTabs groups fields by tab (untabbed fields in the default tab) as a
  segmented tablist; a tab holding invalid fields after a 422 shows a
  count badge and the form switches to the first invalid field
- switch, checkbox and relation join the renderer registry: toggle cards
  (role=switch, 20px checkbox) keep a numeric value numeric; relation
  fields are read-only labels from meta.labels, a searchable single
  select over fields/{field}/options with emptyOption first, or ordered
  removable chips with an appending search (300 ms debounce, 20 per
  page, more on scroll or the more action)
- FormView gets the back button, record title and update subtitle, a
  sticky footer (Usuń with deleteConfirm then DELETE, Anuluj, Zapisz i
  zamknij to the mapped redirectClose, Zapisz), and asks before leaving a
  dirty form on any route change plus a beforeunload guard
- Settings: the rail pins Ustawienia to the bottom when /settings is
  non-empty; /settings lists pages by category; /settings/:code renders
  the settings schema through FormGrid and the registry, PUTs the values
  and maps a 422 like the record form
- New backend::lang keys (form.more_options, tab_default, discard,
  settings.back); form and settings smoke tests; boardwalk/dist rebuilt

admin/src/components/form/registry.ts

@@ -1,11 +1,15 @@
 // Field renderer registry (D-05). A form field's `type` selects the control
 // component; any type without a renderer gets UnsupportedField, the design's
-// dashed box, so an unknown type never breaks the form. Phase 10.1 turns this
-// seam into the plugin extension point.
+// dashed box, so an unknown type never breaks the form. The relation manager
+// arrives with its own component in a later plan. Phase 10.1 turns this seam
+// into the plugin extension point.
 import type { Component } from 'vue'
 import type { ControllerParams, FormField, RelationOption } from '../../api/types'
+import CheckboxField from './fields/CheckboxField.vue'
 import DropdownField from './fields/DropdownField.vue'
 import NumberField from './fields/NumberField.vue'
+import RelationField from './fields/RelationField.vue'
+import SwitchField from './fields/SwitchField.vue'
 import TextField from './fields/TextField.vue'
 import TextareaField from './fields/TextareaField.vue'
 import UnsupportedField from './fields/UnsupportedField.vue'
@@ -30,10 +34,13 @@ const renderers = new Map<string, Component>([
   ['textarea', TextareaField],
   ['number', NumberField],
   ['dropdown', DropdownField],
+  ['switch', SwitchField],
+  ['checkbox', CheckboxField],
+  ['relation', RelationField],
 ])
 
 /** Types whose control shows the label itself (toggle cards). */
-const selfLabelled = new Set<string>()
+const selfLabelled = new Set<string>(['switch', 'checkbox'])
 
 export function rendererFor(type: string): Component {
   return renderers.get(type) ?? UnsupportedField
@@ -82,3 +89,16 @@ export function controlClass(invalid: boolean | undefined): string {
     invalid ? 'border-danger' : 'border-border-strong',
   ].join(' ')
 }
+
+/** Truthiness of a stored toggle value (true, 1, "1", "true"). */
+export function toggleOn(value: unknown): boolean {
+  if (typeof value === 'string') {
+    return value !== '' && value !== '0' && value.toLowerCase() !== 'false'
+  }
+  return Boolean(value)
+}
+
+/** A toggle's next value in the stored value's own type (1/0 or boolean). */
+export function toggleValue(current: unknown, on: boolean): boolean | number {
+  return typeof current === 'number' ? (on ? 1 : 0) : on
+}