Stop optional image pruning after failed Tea login setup

Guard failed cleanup login setup before dependent package operations; preserve successful and optional cleanup semantics. Required contract CI 20382 passed. Exact task-specific Human review-count exception is recorded on t-c1070dtgpqqy; official architect review 8504 approved this head. No authentication repair, tag movement or consumer activation.

Authored-By: Codex (GPT-5) <noreply@openai.com>

action.yaml

@@ -78,8 +78,11 @@ runs:
         KEEP: ${{ inputs.keep }}
       run: |
         set -euo pipefail
-        tea login add --name ci --url https://code.fritzlab.net \
-          --token "$TOKEN" --no-version-check >/dev/null 2>&1 || true
+        if ! tea login add --name ci --url https://code.fritzlab.net \
+          --token "$TOKEN" --no-version-check >/dev/null 2>&1; then
+          echo "::warning::image-push prune failed at login_setup; package cleanup skipped" >&2
+          exit 1
+        fi
         # Paginate the package list. The org has more container versions than a
         # single API page returns (Gitea caps page size at MAX_RESPONSE_ITEMS),
         # so an unpaginated call silently drops a package's older tags from the