fix(focas): serialize per-device wire I/O + bound reads; tolerate AdminUI config formats

Equipment tags were stuck at Bad_WaitingForInitialData on the deployed driver: the equipment poll, fixed-tree loop, probe and recycle shared one FOCAS/2 socket with no serialization, and the steady-state read had no timeout — concurrent reads collided and a stalled read hung forever, never overwriting the node's initial-data seed.

- SynchronizedFocasClient: per-device SemaphoreSlim gate + per-call timeout around every wire op (Connect/Probe gated, not double-bounded); wired in EnsureConnectedAsync. ReadAsync/WriteAsync map a per-call timeout to BadCommunicationError instead of rethrowing.
- FlexibleStringConverter on FOCAS config Series: the AdminUI persists the enum as a number ("series":6); accept number-or-string instead of throwing -> stub.
- FocasHostAddress.TryParse tolerates a scheme-less {ip}[:{port}] (AdminUI hostAddress form); canonical focas:// unchanged, malformed schemes still rejected.

247 FOCAS tests green; each fix has a regression test. Live-validated on wonder-app-vd03 (tags read Good).

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Tests/FocasDriverProbeTests.cs

@@ -70,9 +70,10 @@ public sealed class FocasDriverProbeTests
     [Fact]
     public async Task MalformedHostAddress_Returns_OkFalse_WithNoHostPortMessage()
     {
-        // "not-a-focas-url" is not a focas:// URL — TryParse returns null.
+        // A foreign URI scheme ("http://…") is rejected by TryParse → null. (A bare
+        // "{ip}[:{port}]" without a scheme is now tolerated, so it can't be the malformed case.)
         var result = await Probe.ProbeAsync(
-            "{\"devices\":[{\"hostAddress\":\"not-a-focas-url\"}]}",
+            "{\"devices\":[{\"hostAddress\":\"http://10.0.0.5/\"}]}",
             TimeSpan.FromSeconds(3),
             TestContext.Current.CancellationToken);