fix(ci): drop upload-artifact@v4 (unsupported by Gitea Actions/GHES)

The static gate passes (lint + Kyverno L0 + L1 render) but the trailing
actions/upload-artifact@v4 step fails with "not supported on GHES" — Gitea Actions
does not implement the artifact-v2 backend — and its always() failure sank the whole
job. Remove the step; JUnit/coverage remain in the job workspace. Re-add via the
@v3 action or Gitea's artifact backend later if retention is needed.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

.gitea/workflows/gate.yml

@@ -60,15 +60,11 @@ jobs:
       - name: Static gate — lint + Kyverno L0 + L1 render
         run: make -C ci lint l0 l1
 
-      - name: Upload gate artifacts
-        if: always()
-        uses: actions/upload-artifact@v4
-        with:
-          name: gate-junit-coverage
-          path: |
-            results/junit/*.xml
-            reports/coverage/**
-          if-no-files-found: ignore
+      # NOTE: no actions/upload-artifact step. Gitea Actions rejects upload-artifact@v4
+      # ("not supported on GHES" — Gitea does not implement the artifact-v2 backend), which
+      # would fail the job even on a green gate. JUnit + coverage are written under
+      # conformance/_artifacts/ in the job workspace; wire artifact upload later via the
+      # Gitea-compatible @v3 action or Gitea's own artifact backend if retention is wanted.
 
   # ───────────────────────────────────────────────────────────────────────────
   # PLACEHOLDER — NOT WIRED (STOP-and-report item, WS-GITOSS Phase 6).