fix(ci): grant issues:write to security audit workflow

rustsec/audit-check files an advisory issue when warnings are found,
which currently fails with "Resource not accessible by integration"
because GITHUB_TOKEN only has contents:read.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: lfrancke

.github/workflows/security_audit.yaml

@@ -9,6 +9,7 @@ on:
 
 permissions:
   contents: read
+  issues: write
 
 jobs:
   audit: