feat(frontend): tagDirectory rename and merge store actions

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/stores/tagDirectory.js

@@ -45,6 +45,38 @@ export const useTagDirectoryStore = defineStore('tagDirectory', () => {
   function setKind(k) { kind.value = k; reset() }
   function setQuery(text) { q.value = text; reset() }
 
+  async function rename(id, name) {
+    try {
+      const body = await api.patch(`/api/tags/${id}`, { body: { name } })
+      const card = cards.value.find((c) => c.id === id)
+      if (card) card.name = body.name
+      return { tag: body }
+    } catch (e) {
+      if (e.status === 409 && e.body && e.body.target) {
+        const card = cards.value.find((c) => c.id === id)
+        return {
+          collision: {
+            sourceId: id,
+            sourceName: card ? card.name : '',
+            target: e.body.target,
+            sourceImageCount: e.body.source_image_count,
+            willAlias: e.body.will_alias
+          }
+        }
+      }
+      throw e
+    }
+  }
+
+  async function merge(sourceId, targetId) {
+    const result = await api.post(`/api/tags/${sourceId}/merge`, {
+      body: { target_id: targetId }
+    })
+    const idx = cards.value.findIndex((c) => c.id === sourceId)
+    if (idx !== -1) cards.value.splice(idx, 1)
+    return result
+  }
+
   const hasMore = computed(() => !started || nextCursor.value !== null)
   const isEmpty = computed(
     () => !loading.value && cards.value.length === 0 && error.value === null
@@ -52,6 +84,6 @@ export const useTagDirectoryStore = defineStore('tagDirectory', () => {
 
   return {
     cards, loading, error, kind, q, hasMore, isEmpty,
-    loadMore, reset, setKind, setQuery
+    loadMore, reset, setKind, setQuery, rename, merge
   }
 })