SearchForm: fix inconsistent/mixed search results

- SearchForm.vue: route Enter key through submit() (native form submit
  interception) so it behaves like the button; fix autocomplete array
  mutation during iteration in the typed watcher.
- Base.vue: parse terms consistently in beforeRouteUpdate; render items
  via displayedItems (drops sparse holes); only mount infinite-loading
  after the first page and reset it per search via :identifier.
- search store: guard against stale async responses (searchId); place
  each page at its offset instead of concatenating in arrival order,
  which mixed pages when a later page resolved first.

web/themes/custom/materiotheme/vuejs/components/Form/SearchForm.vue

@@ -135,16 +135,17 @@ export default {
       //   let tag_list = n
       // }
       // remove terms from autocomplete if removed from typed
+      if (typeof n !== 'string') {
+        return
+      }
       const r = /,\s?$/ // remove last comma space
       let tag_list = n.replace(r,'').split(', ')
       console.log('watch typed tag_list', tag_list)
       console.log('watch typed autocomplete before', this.autocomplete)
-      this.autocomplete.forEach( (term,index,array)  => {
-        console.log("watch typed autocomplete term", term, index, array)
-        if (tag_list.indexOf(term.label) < 0) {
-          this.autocomplete.splice(index,1)
-        }
-      });
+      // Keep only the terms whose label is still present in the typed text.
+      // Filtering into a new array avoids skipping items when splicing during
+      // iteration (which left stale terms in autocomplete, corrupting `terms`).
+      this.autocomplete = this.autocomplete.filter(term => tag_list.indexOf(term.label) >= 0)
       console.log('watch typed autocomplete after', this.autocomplete)
     },
     keys(n, o){
@@ -166,6 +167,20 @@ export default {
   mounted(){
     // console.log('SearchForm mounted')
     Drupal.attachBehaviors(this.$el);
+
+    // Route the native form submission (Enter key) through the same submit()
+    // method as the button (@click.prevent="submit"). Without this, pressing
+    // Enter either triggers a native POST reload or only fills the jQuery UI
+    // autocomplete selection, so keys/terms sent to the backend differ from a
+    // button click and the search results are inconsistent.
+    // Note: when the autocomplete menu is open, jQuery UI handles Enter itself
+    // (selects the highlighted suggestion) and prevents this submit event, which
+    // is the intended behaviour.
+    this.$el.addEventListener('submit', (e) => {
+      e.preventDefault()
+      this.submit()
+    })
+
     // get the search input
     this.$input = this.$el.querySelector('#edit-search')
     // // focus on input