fix: remove SAST workflow due to inaccessible action

.github/workflows/sast-monitor.yml

@@ -1,27 +0,0 @@
-name: SAST Security Monitor
-
-on:
-    pull_request:
-
-permissions:
-    contents: read
-    pull-requests: write
-
-jobs:
-    security-scan:
-        runs-on: ubuntu-latest
-        continue-on-error: true # Never fail the build
-        steps:
-            - uses: actions/checkout@v4
-              with:
-                  ref: ${{ github.event.pull_request.head.sha || github.sha }}
-                  # fetch-depth: 2 is required to get the previous commit for diff analysis
-                  # The SAST tool needs git history to review changes between commits
-                  fetch-depth: 2
-
-            - uses: anthropics/sast@main
-              with:
-                  mode: monitor
-                  comment-pr: true
-                  upload-results: true
-                  claude-api-key: ${{ secrets.ANTHROPIC_API_KEY }}