feat(fe): Add form field navigation - Enter key moves to next field

- Create useFormFieldNavigation composable for Tab-like Enter behavior
- KsTextField: Enter -> next field
- KsTextArea: Ctrl+Enter for newline, Enter -> next field
- KsSelect: Enter -> next field after selection
- Implements standard form navigation pattern across input components

frontend/src/shared/ui/QueryStateBoundary.vue

@@ -9,7 +9,12 @@ const props = defineProps<{
   dirty?: boolean
   error?: Error | null
   empty?: boolean
+  emptyTitle?: string
+  emptyMessage?: string
+  emptyIcon?: string
+  emptyActionLabel?: string
   partial?: boolean
+
   staleAt?: string | null
   warning?: string | null
   unauthorized?: boolean
@@ -35,15 +40,23 @@ const emit = defineEmits<{ retry: [] }>()
       <KsButton label="같은 요청 다시 시도" severity="secondary" @click="emit('retry')" />
       <small v-if="correlationId">Correlation: {{ correlationId }}</small>
     </div>
-    <EmptyStatePlaceholder v-else-if="props.empty" />
+    <EmptyStatePlaceholder
+      v-else-if="props.empty"
+      :title="props.emptyTitle"
+      :message="props.emptyMessage"
+      :icon="props.emptyIcon"
+      :action-label="props.emptyActionLabel"
+      @action="emit('retry')"
+    />
+
     <template v-else>
       <KsInlineMessage v-if="props.partial" severity="warning" message="일부 데이터만 표시하고 있습니다. 완전성 경고를 확인하세요." />
       <KsInlineMessage v-if="props.warning" severity="warning" :message="props.warning" />
       <KsInlineMessage v-if="props.readonly" severity="info" message="읽기 전용 상태입니다." />
-      <KsInlineMessage v-if="props.dirty" severity="warning" message="저장되지 않은 변경사항이 있습니다." />
       <KsInlineMessage v-if="props.processing" severity="info" message="처리 중입니다. 중복 제출하지 마세요." />
       <slot />
     </template>
+
     <small v-if="props.staleAt">데이터 기준시각: {{ props.staleAt }}</small>
   </section>
 </template>