Multiple changes

- backend: add summoner spells
- backend: add build variants
- backend: builds are now storing full tree with runes (keystones)
- backend: build trees are split on starter items and merged on runes
- frontend: computing core tree now
- frontend: variant selectors

frontend/components/build/BuildVariantSelector.vue

@@ -7,12 +7,18 @@ const props = defineProps<{
   keystore: Map<number, Perk>
   itemMap: Map<number, Item>
   pickrate: number
+  selected: boolean
+  index: number
+}>()
+
+const emit = defineEmits<{
+  select: [index: number]
 }>()
 </script>
 
 <template>
   <div class="build-variant-selector">
-    <div :class="['build-variant-card', { selected: true }]">
+    <div :class="['build-variant-card', { selected }]" @click="emit('select', index)">
       <div class="variant-content">
         <!-- Keystone -->
         <NuxtImg