add gitleaks baseline and update security scan workflow

Configure Gitleaks to use baseline file for secret detection, allowing tracking of known findings and only failing on new secrets.

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

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

Author: nicolasbagatello

.github/workflows/security-scan.yml

@@ -67,7 +67,7 @@ jobs:
       - name: Run Gitleaks
         uses: gitleaks/gitleaks-action@v2
         with:
-          args: detect --source . --verbose --redact
+          args: detect --source . --verbose --redact --baseline-path gitleaks-baseline.json
 
   ###############################################
   # 3. Run CodeQL using auto-detected languages

gitleaks-baseline.json

@@ -0,0 +1 @@
+[]