feat(10-03): search, sort, filter, page and bulk-delete any list

- List state (search, sort, dir, page, per_page, filter[<name>]) lives in
  the URL query through parseListQuery/toListQuery; every change is a
  router replace and clears the selection; search is debounced 300 ms and
  resets the page
- DataTable renders the schema columns with a tri-state page checkbox,
  asc/desc/none sorting with aria-sort, selected rows, a sticky header,
  eight skeleton rows while loading and an empty slot
- CellValue renders text (muted dash when empty, arrays comma-joined),
  datetime as YYYY-MM-DD HH:mm and switch as the Tak/Nie pills
- The heading shows the plural recordCount and the create button;
  delete sits in the toolbar, disabled without a selection, and confirms
  with the plural deleteConfirm in a Reka alert dialog before POSTing
  bulk-delete; a 409 shows a danger toast
- FilterBar renders switch (JSON of the option value), daterange
  (from..to) and scope filters (choices from filters/{scope}/options)
- Pagination shows the range, the per-page select over perPageOptions
  (hidden with one choice) and a pager with ellipsis
- The tracer smoke test skips the new checkbox column; new backend::lang
  list keys; boardwalk/dist rebuilt

admin/src/components/ui/ConfirmDialog.vue

@@ -0,0 +1,75 @@
+<script setup lang="ts">
+import {
+  AlertDialogCancel,
+  AlertDialogContent,
+  AlertDialogDescription,
+  AlertDialogOverlay,
+  AlertDialogPortal,
+  AlertDialogRoot,
+  AlertDialogTitle,
+} from 'reka-ui'
+import { t } from '../../app/i18n'
+
+// Confirmation (Reka AlertDialog: role alertdialog, focus trapped, Esc
+// cancels, focus returns to the trigger). Text only: messages come from the
+// server and are never rendered as HTML.
+withDefaults(
+  defineProps<{
+    open: boolean
+    message: string
+    title?: string
+    confirmLabel?: string
+    cancelLabel?: string
+    danger?: boolean
+  }>(),
+  { title: undefined, confirmLabel: undefined, cancelLabel: undefined, danger: false },
+)
+const emit = defineEmits<{ 'update:open': [open: boolean]; confirm: []; cancel: [] }>()
+
+// Closing any other way than the confirm button (Esc, Anuluj) cancels.
+function onOpenChange(open: boolean): void {
+  emit('update:open', open)
+  if (!open) {
+    emit('cancel')
+  }
+}
+
+function onConfirm(): void {
+  emit('confirm')
+  emit('update:open', false)
+}
+</script>
+
+<template>
+  <AlertDialogRoot :open="open" @update:open="onOpenChange">
+    <AlertDialogPortal>
+      <AlertDialogOverlay class="fixed inset-0 z-40 bg-overlay" />
+      <AlertDialogContent
+        data-confirm-dialog
+        class="fixed top-1/2 left-1/2 z-50 flex w-[calc(100%-32px)] max-w-[440px] -translate-x-1/2 -translate-y-1/2 flex-col gap-4 rounded-modal bg-surface p-6 text-text shadow-pop"
+      >
+        <AlertDialogTitle class="text-[20px] font-bold tracking-[-0.01em]">
+          {{ title ?? t('backend::lang.form.confirm') }}
+        </AlertDialogTitle>
+        <AlertDialogDescription class="text-muted">{{ message }}</AlertDialogDescription>
+        <div class="flex gap-2.5">
+          <AlertDialogCancel
+            data-action="cancel"
+            class="inline-flex h-button flex-1 items-center justify-center rounded-control border border-border-strong bg-surface font-semibold hover:bg-hover"
+          >
+            {{ cancelLabel ?? t('backend::lang.form.cancel') }}
+          </AlertDialogCancel>
+          <button
+            type="button"
+            data-action="confirm"
+            :class="danger ? 'bg-danger text-white' : 'bg-primary text-on-primary'"
+            class="inline-flex h-button flex-1 items-center justify-center rounded-control font-semibold hover:opacity-90"
+            @click="onConfirm"
+          >
+            {{ confirmLabel ?? t('backend::lang.form.confirm') }}
+          </button>
+        </div>
+      </AlertDialogContent>
+    </AlertDialogPortal>
+  </AlertDialogRoot>
+</template>

admin/src/components/ui/confirm.ts

@@ -0,0 +1,31 @@
+// Promise-based confirmation for ConfirmDialog: `await ask(text)` resolves
+// true on confirm and false on Anuluj, Esc or a second request.
+import { ref } from 'vue'
+
+export interface ConfirmRequest {
+  message: string
+  confirmLabel?: string
+  danger?: boolean
+}
+
+export function useConfirm() {
+  const request = ref<ConfirmRequest | null>(null)
+  let resolver: ((ok: boolean) => void) | null = null
+
+  function settle(ok: boolean): void {
+    const resolve = resolver
+    resolver = null
+    request.value = null
+    resolve?.(ok)
+  }
+
+  function ask(next: ConfirmRequest): Promise<boolean> {
+    settle(false)
+    request.value = next
+    return new Promise<boolean>((resolve) => {
+      resolver = resolve
+    })
+  }
+
+  return { request, ask, confirm: () => settle(true), cancel: () => settle(false) }
+}