Add failing ORC thread-safety regressions and run all suites with nimble test

tests/README.md

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+# Regression tests
+
+These tests assert the intended behavior. Known bugs are ordinary failures,
+not expected failures: the tasks should become green as the defects are fixed.
+
+Run from the repository root:
+
+| Command | Coverage |
+| --- | --- |
+| `nimble test` | All unit, regression, and ThreadSanitizer tests under ORC with threads enabled |
+| `nimble testUnit` | Existing embedded unit tests |
+| `nimble testRegression` | Configuration freshness, refresh failure recovery, appender-state cleanup, and writer shutdown |
+| `nimble testThreadSafety` | Separate ThreadSanitizer processes for service ownership, custom state, and formatter closures, plus an independent-service control |
+
+`nimble test` attempts every suite even if an earlier suite fails to compile or
+run, summarizes the failing suites, and exits unsuccessfully if any suite fails.
+The subset commands use the same build and execution procedures as the full run.
+
+Executables are generated in ignored `tests/bin/`. The shutdown child is built
+with `-d:multithreaded`; `--threads:on` alone does not enable background writers.
+The other tests do not need background I/O to exercise ownership.
+
+The full run and the sanitizer subset require Linux, Bash, GNU `timeout`, and a
+C compiler and runtime supporting `-fsanitize=thread`. The sanitizer instruments
+the generated Nim C code, including the ORC runtime. A sanitizer report, timeout,
+crash, or runtime startup
+failure causes a nonzero result; consult the diagnostic to distinguish these.
+Each scenario runs separately so one failure does not hide another. To inspect
+one scenario after building:
+
+```sh
+TSAN_OPTIONS=halt_on_error=1:exitcode=66 timeout 30s tests/bin/thread_safety service
+```
+
+The worker start barrier ensures argument setup finishes before the concurrent
+operations begin. Parent owners survive until all workers join. Custom-state
+and closure tests only read application data; their concurrent writes are the
+implicit ownership operations caused by cloning and destruction. The independent
+case creates a separate service inside each worker and should pass. Custom-state
+and formatter cloning is serialized with a lock, matching configuration refresh;
+the copied appenders are used and destroyed outside that lock.
+
+The three in-process regression tests are deterministic. Shutdown tests launch
+a fresh process for each destination and check all 10,000 messages after normal
+exit, using isolated temporary paths and a 15-second deadline. They exercise the
+real exit hook without sleeps to hide queued-message loss. Like the race tests,
+the shutdown failure can depend on scheduling; a passing run is not proof of
+thread safety or reliable draining.
+
+This suite does not yet force an active producer/channel-close race, separately
+exercise the shared `testutil.LoggedMessages` graph, or exhaust ORC cycle-collector
+interleavings. It provides targeted regressions for the reproduced ownership
+defects and the configuration, cleanup, and shutdown findings.