ci: gate element-hq-only workflows on fork

Skip upstream deploy/publish/release, org automation, translations and
PR previews via a repo guard; allow PRs to release/* base branches.

.github/workflows/release.yml

@@ -14,6 +14,7 @@ concurrency: ${{ github.workflow }}
 permissions: {}
 jobs:
     release:
+        if: ${{ github.repository == 'element-hq/element-web' }}
         uses: matrix-org/matrix-js-sdk/.github/workflows/release-make.yml@develop # zizmor: ignore[unpinned-uses]
         permissions:
             contents: write
@@ -34,6 +35,7 @@ jobs:
             version-dirs: apps/web apps/desktop
 
     check:
+        if: ${{ github.repository == 'element-hq/element-web' }}
         name: Post release checks
         needs: release
         runs-on: ubuntu-24.04