test(playwright): add playwright report to track changes + correct playwright parameters

ci: fix actions/checkout@v6 → @v4 (v6 does not exist)

GitHub started rejecting invalid action versions at parse time,
causing every CI run to fail with 0s / 'workflow file issue'
before any jobs could start.

 * test(e2e): only no retry
 * test(e2e): use static name in tests to facilitate screenshot comparaison
 * test(e2e): update linux screenshots
 * test(e2e): adapt test due to user-vignette generation

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.github/workflows/docker-publish.yml

@@ -39,7 +39,7 @@ jobs:
       DATABASE_URL: "postgres://postgres:postgres@localhost/oxicloud_test"
     steps:
       - name: Checkout
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
         with:
           # Build the exact tag behind the published release or manual dispatch.
           ref: ${{ github.event.inputs.version || github.event.release.tag_name || github.ref }}
@@ -61,7 +61,7 @@ jobs:
     needs: test
     steps:
       - name: Checkout
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
         with:
           # Build the exact tag behind the published release or manual dispatch.
           ref: ${{ github.event.inputs.version || github.event.release.tag_name || github.ref }}