Merge Country Posters' pane address (shareable pages P2)

plugin-designs/country-posters/country-posters-mfe.vue

@@ -32,6 +32,7 @@
  */
 import { ref, computed, inject, onMounted, onBeforeUnmount } from 'vue'
 import { buildPaneColumn, PANE_GRID_STYLES } from '@map/layouts/pane-wrapper/pane-wrapper.js'
+import { urlOwnerOf, ownAddress } from '@map/composables/useViewAddress.js'
 import { useShadowStyles } from '@map/composables/useShadowStyles.js'
 import ViewSelect from '@map/components/ViewSelect.vue'
 import { countryName } from '@map/utils/countryName.js'
@@ -104,6 +105,11 @@ const view = computed({
 })
 let column = null
 let offScroll = null
+let offOwn = null
+// The page address (useViewAddress): ?pane= is the open view ('map'; the first pane is the default and never written).
+// On this composite's own leaf it owns the address (ownAddress); nested in a shell it announces and the shell writes.
+// The India pane exists only in an opted-in preview, so ?pane=india names nothing anywhere else.
+const owner = () => urlOwnerOf(cfg.value)
 
 // PAGE-LEVEL config keys a pane INHERITS from the host page. A cap-4 composite
 // nests children as custom elements in THIS document, so anything the generator
@@ -209,8 +215,9 @@ function onShowOnMap(e) {
 
 onMounted(() => {
   if (!stage.value) return
-  column = buildPaneColumn(spec.value, { host: stage.value })
+  column = buildPaneColumn(spec.value, { host: stage.value, address: { owner } })
   if (!column) return
+  offOwn = ownAddress(stage.value, owner)
   for (const pane of column.panes) {
     if (!pane.config) continue
     // ★ KEEP THE ELEMENT. It used to be created and dropped on the same line, so there was no
@@ -236,6 +243,7 @@ onMounted(() => {
 onBeforeUnmount(() => {
   window.removeEventListener(SHOW_ON_MAP, onShowOnMap)
   offScroll?.()
+  offOwn?.()
   column?.destroy()
   column = null
 })