ci: remove continue-on-error (full suite now passes on all platforms)

Step 8 was made non-blocking while investigating; now that the 3 CI-only
failures are fixed (material-inventory.json tracked + config_diagnostic
assertion conditional), the full suite passes on all 6 matrix jobs.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: QUSETIONS

.github/workflows/ci.yml

@@ -39,5 +39,4 @@ jobs:
         run: python -m pytest tests/test_packaging.py -q
 
       - name: Run test suite
-        continue-on-error: true
-        run: python -m pytest -q -x --tb=short
+        run: python -m pytest -q --tb=short