Pin release-workflow actions to commit SHAs + least-privilege token (#862)

Every `uses:` in build-release.yml was a mutable tag; the `release` job has
`contents: write` and publishes the binaries users install, so a compromised
action could tamper the release. Action tag-hijacking keeps recurring
(aquasecurity/trivy-action, 75 tags, Mar 2026 TeamPCP; tj-actions, 2025;
codfish/semantic-release-action, Jun 2026) and SHA-pinned workflows were immune
each time. Pin all six actions to the commit each @major resolves to today
(concrete version in a trailing comment; setup-uv's annotated tag dereferenced
to its commit, not the tag object, so Dependabot tracks it). Also add a
top-level `permissions: contents: read` (the release job keeps its explicit
write) and `persist-credentials: false` on the build checkout.

actionlint passes. Pairs with #860 (Dependabot github-actions keeps the pins
current).

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.github/workflows/build-release.yml

@@ -6,6 +6,9 @@ on:
       - 'v*'
   workflow_dispatch:
 
+permissions:
+  contents: read
+
 jobs:
   build:
     strategy:
@@ -24,13 +27,15 @@ jobs:
     runs-on: ${{ matrix.os }}
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262  # v4.4.0
+        with:
+          persist-credentials: false
 
-      - uses: actions/setup-python@v5
+      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065  # v5.6.0
         with:
           python-version: '3.12'
 
-      - uses: astral-sh/setup-uv@v5
+      - uses: astral-sh/setup-uv@d4b2f3b6ecc6e67c4457f6d3e41ec42d3d0fcb86  # v5.4.2
 
       - name: Build
         shell: bash
@@ -50,7 +55,7 @@ jobs:
             tar -C dist/release -czvf "dist/release/strix-${VERSION}-${{ matrix.target }}.tar.gz" "strix-${VERSION}-${{ matrix.target }}"
           fi
 
-      - uses: actions/upload-artifact@v4
+      - uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02  # v4.6.2
         with:
           name: strix-${{ matrix.target }}
           path: |
@@ -65,13 +70,13 @@ jobs:
       contents: write
 
     steps:
-      - uses: actions/download-artifact@v4
+      - uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093  # v4.3.0
         with:
           path: release
           merge-multiple: true
 
       - name: Create Release
-        uses: softprops/action-gh-release@v2
+        uses: softprops/action-gh-release@3bb12739c298aeb8a4eeaf626c5b8d85266b0e65  # v2.6.2
         with:
           prerelease: ${{ !startsWith(github.ref, 'refs/tags/') }}
           generate_release_notes: true