ci: add Qodana baseline (qodana.sarif.json)

The workflow expects a qodana.sarif.json baseline; without it Qodana compares against an empty report and reports all 1225 pre-existing issues as NEW. This baseline was generated with Qodana Community for .NET 2026.1 against the integration branch and will be used by PRs targeting main after merge.

Co-Authored-By: Afonso Dutra Nogueira Filho <afonsoft@gmail.com>

Author: devin-ai-integration[bot]