docs(llms.txt): adiciona stack técnico e remove links inexistentes

Inclui stack no cabeçalho do arquivo e remove referências a AGENTS.md,
robots.txt e sitemap.xml que não existem no repositório.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

public/llms.txt

@@ -1,6 +1,8 @@
 # OpenMonetis
 
 > OpenMonetis is a self-hosted personal finance web app for manual financial control. It helps users manage accounts, cards, invoices, budgets, notes, reports, attachments, and AI-generated insights. The product UI is in Brazilian Portuguese, the codebase uses English folder and import names, and there is no hosted SaaS version.
+>
+> **Stack:** Next.js 16, React 19, PostgreSQL, Drizzle ORM, Better Auth, Tailwind CSS 4, shadcn/ui. Package manager: pnpm. Linter: Biome.
 
 OpenMonetis is meant to be deployed by the user on their own machine or server.
 There is no Open Finance or automatic bank synchronization.
@@ -24,13 +26,8 @@ The public website is mainly a landing page; the main technical documentation li
 ## Architecture
 
 - [CLAUDE.md](https://github.com/felipegcoutinho/openmonetis/blob/main/CLAUDE.md): Project architecture, naming rules, query rules, and feature checklist
-- [AGENTS.md](https://github.com/felipegcoutinho/openmonetis/blob/main/AGENTS.md): Agent-oriented project instructions and repository context
 
 ## Related Projects
 
 - [OpenMonetis Companion](https://github.com/felipegcoutinho/openmonetis-companion): Android app that captures bank notifications and sends them to the OpenMonetis inbox for review
 
-## Optional
-
-- [robots.txt](/robots.txt): Crawl policy for the public site
-- [sitemap.xml](/sitemap.xml): Public sitemap