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>

.claude/settings.local.json

@@ -11,7 +11,10 @@
       "Bash(curl -s http://localhost:8010/docs -o /dev/null -w \"status:%{http_code}\\\\n\")",
       "Bash(git add *)",
       "Bash(git commit -m ' *)",
-      "PowerShell(Get-Process | Where-Object { $_.ProcessName -match \"python|uvicorn\" } | Select-Object Id, ProcessName, Path)"
+      "PowerShell(Get-Process | Where-Object { $_.ProcessName -match \"python|uvicorn\" } | Select-Object Id, ProcessName, Path)",
+      "Bash(curl -s -o /dev/null -w \"%{http_code}\\\\n\" http://localhost:8000/health --max-time 5)",
+      "Bash(curl -s -N -X POST http://localhost:8000/chat/stream -H \"Content-Type: application/json\" -d '{\"message\":\"latest news about python 3.14 release\",\"model\":\"bedrock/jp.anthropic.claude-sonnet-4-6\"}' --max-time 60)",
+      "Bash(curl -s -N -X POST http://localhost:8000/chat/stream -H \"Content-Type: application/json\" -d '{\"message\":\"latest news about python 3.14 release\",\"model\":\"bedrock/jp.anthropic.claude-sonnet-4-6\"}' --max-time 90)"
     ]
   }
 }