fix(driver-twincat): resolve Low code-review findings (Driver.TwinCAT-004,006,014,015,016)

- Driver.TwinCAT-004: corrected the IEC time-type inline comments;
  documented that the driver currently surfaces them as raw UInt32
  counters.
- Driver.TwinCAT-006: ResolveHost returns a documented UnresolvedHost
  sentinel when no devices are configured instead of returning the
  logical DriverInstanceId (which never matches GetHostStatuses).
- Driver.TwinCAT-014: wired Probe.Timeout into the probe-loop call and
  added a NotificationMaxDelayMs config knob threaded through
  AddNotificationAsync.
- Driver.TwinCAT-015: Dispose() runs a genuinely synchronous teardown
  with bounded waits (no sync-over-async deadlock pattern).
- Driver.TwinCAT-016: pinned the Structure-tag rejection and the
  probe-loop vs read disposal race with regression tests.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.Tests/TwinCATCapabilityTests.cs

@@ -217,12 +217,14 @@ public sealed class TwinCATCapabilityTests
     }
 
     [Fact]
-    public async Task ResolveHost_falls_back_to_DriverInstanceId_when_no_devices()
+    public async Task ResolveHost_falls_back_to_unresolved_sentinel_when_no_devices()
     {
+        // Driver.TwinCAT-006: empty-string sentinel — DriverInstanceId is a config-DB key, not
+        // a host address, so it would collide with no GetHostStatuses() row.
         var drv = new TwinCATDriver(new TwinCATDriverOptions(), "drv-1");
         await drv.InitializeAsync("{}", CancellationToken.None);
 
-        drv.ResolveHost("anything").ShouldBe("drv-1");
+        drv.ResolveHost("anything").ShouldBe(TwinCATDriver.UnresolvedHostSentinel);
     }
 
     // ---- helpers ----