Initial commit: clean project structure

- Backend: FastAPI + SQLAlchemy + Celery (Python 3.11+)
- Frontend: Vue 3 + TypeScript + Pinia + Tailwind
- Admin Frontend: separate Vue 3 app for management
- Docker Compose: 9 services orchestration
- Specs: design prototypes, memory system PRD, product roadmap

Cleanup performed:
- Removed temporary debug scripts from backend root
- Removed deprecated admin_app.py (embedded UI)
- Removed duplicate docs from admin-frontend
- Updated .gitignore for Vite cache and egg-info

frontend/src/components/ui/EmptyState.vue

@@ -0,0 +1,45 @@
+<script setup lang="ts">
+import type { Component } from 'vue'
+import BaseButton from './BaseButton.vue'
+
+const props = withDefaults(
+  defineProps<{
+    icon: Component
+    title: string
+    description: string
+    actionText?: string
+    actionTo?: string
+  }>(),
+  {
+    actionText: '',
+    actionTo: '',
+  },
+)
+
+const emit = defineEmits<{ action: [] }>()
+
+function handleAction() {
+  if (!props.actionTo) emit('action')
+}
+</script>
+
+<template>
+  <div class="flex flex-col items-center justify-center text-center py-12">
+    <component :is="props.icon" class="h-14 w-14 text-purple-400" aria-hidden="true" />
+    <h3 class="mt-4 text-xl font-semibold text-gray-800">
+      {{ props.title }}
+    </h3>
+    <p class="mt-2 text-sm text-gray-500">
+      {{ props.description }}
+    </p>
+    <BaseButton
+      v-if="props.actionText"
+      :as="props.actionTo ? 'router-link' : 'button'"
+      :to="props.actionTo || undefined"
+      class="mt-6"
+      @click="handleAction"
+    >
+      {{ props.actionText }}
+    </BaseButton>
+  </div>
+</template>