chore: add required permissions for vulnerability triage workflow

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: msukkari

.github/workflows/vulnerability-triage.yml

@@ -5,6 +5,12 @@ on:
     - cron: '0 13 * * *'
   workflow_dispatch:
 
+permissions:
+  contents: read
+  packages: read
+  security-events: read
+  id-token: write
+
 jobs:
   triage:
     uses: sourcebot-dev/sourcebot/.github/workflows/vulnerability-triage.yml@main