feat(security): fleet-wide workflow hardening (SHA pinning + permissions)

Author: hyperpolymath

.github/workflows/release.yml

@@ -34,7 +34,7 @@ jobs:
           #   mix release
 
       # TODO: Upload build artifacts if needed
-      # - uses: actions/upload-artifact@v4
+      # - uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
       #   with:
       #     name: release-artifacts
       #     path: target/release/
@@ -94,7 +94,7 @@ jobs:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
 
       # TODO: Download build artifacts if uploading to the release
-      # - uses: actions/download-artifact@v4
+      # - uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4
       #   with:
       #     name: release-artifacts
       #     path: artifacts/