feat(agent): add automatic web search and rename uploads dir to workspace

- Add WEB_SEARCH_ENABLED and WEB_SEARCH_MAX_RESULTS config options
- Detect search-intent messages via trigger keywords and inject web
  results into the AI context
- Instruct the system prompt to use web search for factual, current,
  or time-sensitive questions instead of inventing data
- Rename uploads directory from `uploadsfiles/` to `workspace/`,
  updating .gitignore and backup instructions in DEPLOY.md

DEPLOY.md

@@ -216,12 +216,12 @@ Faça backup regular dos arquivos de dados dentro de `/app`:
 - `system_improvements.json`
 - `uploads_metadata.json`
 - pasta `contexts/`
-- pasta `uploadsfiles/`
+- pasta `workspace/`
 
 Exemplo simples de backup diário:
 
 ```bash
-tar czf /root/backups/psagentai-$(date +%F).tar.gz -C /opt/psagentai/app user_profile.json agent_profile.json system_improvements.json uploads_metadata.json contexts uploadsfiles
+tar czf /root/backups/psagentai-$(date +%F).tar.gz -C /opt/psagentai/app user_profile.json agent_profile.json system_improvements.json uploads_metadata.json contexts workspace
 ```
 
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