Watchdogs and timeouts

This bench treats completed responses and intentional timeouts as separate checked outcomes. The build needs no clock or edge configuration:

uv run --frozen cpptb build --project examples/watchdog_timeout --build-dir build

The test starts dut.clk at 10 ns and awaits the DUT-produced dut.response_valid edge directly.

The registered test runs kTransactionCount = 8 normal operations, one raw edge timeout, one expected task timeout, and a cancellable monitor. The pure SV peer mirrors the same count and deadlines.

auto response = co_await with_timeout(
    transaction(dut, word, 3, false), 200_ns);
test.expect_eq("transaction completed", response.has_value(), true);

auto stalled = co_await with_timeout(
    transaction(dut, word, 2, true), 60_ns);
test.expect_eq("stalled transaction timed out", stalled.timed_out(), true);

auto monitor = test.spawn(dormant_monitor(dut));
co_await Delay{3_ns};
monitor.cancel();
co_await monitor;

spawn() returns a Process for joining or cancellation. spawn_detached() is available for roots that need no handle, and TestContext::now() reports the current scheduler time. The public API has no implicit global context.