test: process tests run outside the --parallel pool

The pool workers were made non-daemonic so the operations process
tests could start workers, but a terminated pool (Ctrl-C, --failfast)
left those workers running. The test runner now keeps the test cases
tagged "processes" out of the pool and runs them in the main process
after it. A WAL that cannot be written back before cloning now stops
the run instead of giving clones without tables. One CI leg runs the
suite with --parallel.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

.github/workflows/test.yml

@@ -95,6 +95,11 @@ jobs:
           coverage run manage.py test
           coverage report --skip-covered
 
+      # The project test runner (webvirtcloud/test_runner.py) on one leg
+      - name: Run Test Suite In Parallel
+        if: matrix.python-version == '3.13' && matrix.database == 'sqlite'
+        run: python manage.py test --parallel
+
       # The per-file report of one leg, to see what a change left untested
       - name: Store Coverage Report
         if: always() && matrix.python-version == '3.12' && matrix.database == 'sqlite'