Add Docker/Lightsail deployment, web search summarization, and fix vite peer dep

- Add backend/frontend Dockerfiles, nginx reverse proxy config, and
  docker-compose.yml to run the app on AWS Lightsail; document the setup
  in docs/deploy-lightsail.md. Fix a .gitignore path anchoring bug that
  left backend/knowledge_base/web_search/ untracked instead of ignored.
- Summarize web search results into structured Markdown via LLM before
  saving them to the local knowledge base, and support regenerating
  existing entries from their source URLs (backend/app/core/memory_kb).
- Downgrade vite to ^6 to match @vitejs/plugin-vue's peer dependency
  range, fixing a failing `npm ci` (found while testing the Docker build).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

frontend/.dockerignore

@@ -0,0 +1,3 @@
+node_modules/
+dist/
+.vite/

frontend/Dockerfile

@@ -0,0 +1,12 @@
+FROM node:22-slim AS build
+WORKDIR /app
+COPY package.json package-lock.json ./
+RUN npm ci
+COPY . .
+RUN npm run build
+
+FROM nginx:1.27-alpine
+COPY nginx.conf /etc/nginx/conf.d/default.conf
+COPY --from=build /app/dist /usr/share/nginx/html
+
+EXPOSE 80

frontend/nginx.conf

@@ -0,0 +1,27 @@
+server {
+    listen 80;
+    server_name _;
+
+    root /usr/share/nginx/html;
+    index index.html;
+
+    # SPA フォールバック
+    location / {
+        try_files $uri $uri/ /index.html;
+    }
+
+    # バックエンド API へのリバースプロキシ（/chat/stream は SSE のためバッファリング無効化）
+    location ~ ^/(chat|api|memory|logs|health) {
+        proxy_pass http://backend:8000;
+        proxy_http_version 1.1;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto $scheme;
+
+        proxy_buffering off;
+        proxy_cache off;
+        proxy_read_timeout 300s;
+        chunked_transfer_encoding off;
+    }
+}

frontend/package.json

@@ -20,7 +20,7 @@
     "@types/dompurify": "^3.0.5",
     "@vitejs/plugin-vue": "^5.0.4",
     "typescript": "^5.4.0",
-    "vite": "^8.0.16",
+    "vite": "^6.0.0",
     "vue-tsc": "^2.0.6"
   }
 }