chore: pin all third-party actions to SHA digests

Pin third-party GitHub Actions to immutable SHA digests to prevent
supply chain attacks via tag force-pushing or branch updates.

Actions pinned:
- trufflesecurity/trufflehog (was @main, now SHA)
- sigstore/cosign-installer@v3.8.1
- docker/setup-buildx-action@v3.12.0
- docker/setup-qemu-action@v3.7.0
- docker/login-action@v3.7.0
- goreleaser/goreleaser-action@v6.4.0
- aquasecurity/trivy-action@0.33.1
- github/codeql-action/upload-sarif@v4.32.1
- golangci/golangci-lint-action@v9.2.0
- docker/setup-compose-action@v1.2.0

Version comments added for maintainability.

.github/workflows/release.yaml

@@ -44,25 +44,25 @@ jobs:
         run: npm ci
 
       - name: Install Cosign
-        uses: sigstore/cosign-installer@v3
+        uses: sigstore/cosign-installer@053f9b74638557590800a301da1ba82351507e2c # v3.8.1
 
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
+        uses: docker/setup-buildx-action@8d2750c68a42422c14e847fe6c8ac0403b4cbd6f # v3.12.0
 
       - name: Set up QEMU
-        uses: docker/setup-qemu-action@v3
+        uses: docker/setup-qemu-action@c7c53464625b32c7a7e944ae62b3e17d2b600130 # v3.7.0
         with:
           platforms: all
 
       - name: Log in to GitHub Container Registry
-        uses: docker/login-action@v3
+        uses: docker/login-action@c94ce9fb468520275223c153574b00df6fe4bcc9 # v3.7.0
         with:
           registry: ghcr.io
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Run GoReleaser
-        uses: goreleaser/goreleaser-action@v6
+        uses: goreleaser/goreleaser-action@e435ccd777264be153ace6237001ef4d979d3a7a # v6.4.0
         with:
           distribution: goreleaser
           version: "~> v2"
@@ -71,7 +71,7 @@ jobs:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Scan Docker image with Trivy
-        uses: aquasecurity/trivy-action@0.33.1
+        uses: aquasecurity/trivy-action@b6643a29fecd7f34b3597bc6acb0a98b03d33ff8 # 0.33.1
         with:
           image-ref: "ghcr.io/getprobo/probo:${{ github.ref_name }}"
           format: "sarif"
@@ -82,7 +82,7 @@ jobs:
           severity: "CRITICAL,HIGH"
 
       - name: Upload Trivy scan results to GitHub Security tab
-        uses: github/codeql-action/upload-sarif@v4
+        uses: github/codeql-action/upload-sarif@6bc82e05fd0ea64601dd4b465378bbcf57de0314 # v4.32.1
         if: always()
         with:
           sarif_file: "trivy-results.sarif"