fix(ci): corrige runs-on dos workflows Forgejo para self-hosted

O runner Forgejo esta configurado como self-hosted, entao todos os jobs
precisam usar as labels corretas em vez de ubuntu-latest.

Alteracoes:
- ci-cd-web-desktop.yml: job changes agora usa [self-hosted, linux, vps]
- quality-checks.yml: job lint-test-build agora usa [self-hosted, linux, vps]
- docs/FORGEJO-CI-CD.md: documentacao atualizada com essa diferenca

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.forgejo/workflows/quality-checks.yml

@@ -11,7 +11,7 @@ on:
 jobs:
   lint-test-build:
     name: Lint, Test and Build
-    runs-on: ubuntu-latest
+    runs-on: [ self-hosted, linux, vps ]
     env:
       BETTER_AUTH_SECRET: test-secret
       NEXT_PUBLIC_APP_URL: http://localhost:3000