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).

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.FOCAS/FocasDriver.cs

@@ -306,7 +306,16 @@ public sealed class FocasDriver : IDriver, IReadable, IWritable, ITagDiscovery,
                         Volatile.Read(ref _health).LastSuccessfulRead,
                         $"FOCAS status 0x{status:X8} reading {reference}"));
             }
-            catch (OperationCanceledException) { throw; }
+            catch (OperationCanceledException) when (cancellationToken.IsCancellationRequested) { throw; }
+            catch (OperationCanceledException)
+            {
+                // Per-call timeout (not external cancellation) — the read stalled past the device
+                // Timeout budget. Surface a recoverable comm error so the BadWaitingForInitialData
+                // seed is overwritten and health degrades, instead of the read hanging forever.
+                results[i] = new DataValueSnapshot(null, FocasStatusMapper.BadCommunicationError, null, now);
+                Volatile.Write(ref _health, new DriverHealth(DriverState.Degraded,
+                    Volatile.Read(ref _health).LastSuccessfulRead, $"FOCAS read timed out for {reference}"));
+            }
             catch (Exception ex)
             {
                 results[i] = new DataValueSnapshot(null, FocasStatusMapper.BadCommunicationError, null, now);
@@ -356,7 +365,15 @@ public sealed class FocasDriver : IDriver, IReadable, IWritable, ITagDiscovery,
                 var status = await client.WriteAsync(parsed, def.DataType, w.Value, cancellationToken).ConfigureAwait(false);
                 results[i] = new WriteResult(status);
             }
-            catch (OperationCanceledException) { throw; }
+            catch (OperationCanceledException) when (cancellationToken.IsCancellationRequested) { throw; }
+            catch (OperationCanceledException)
+            {
+                // Per-call timeout (not external cancellation) — the write stalled past the device
+                // Timeout budget. Surface a recoverable comm error rather than aborting the batch.
+                results[i] = new WriteResult(FocasStatusMapper.BadCommunicationError);
+                Volatile.Write(ref _health, new DriverHealth(DriverState.Degraded,
+                    Volatile.Read(ref _health).LastSuccessfulRead, $"FOCAS write timed out for {w.FullReference}"));
+            }
             catch (NotSupportedException nse)
             {
                 results[i] = new WriteResult(FocasStatusMapper.BadNotSupported);
@@ -1113,7 +1130,11 @@ public sealed class FocasDriver : IDriver, IReadable, IWritable, ITagDiscovery,
             device.Client = null;
         }
 
-        device.Client = _clientFactory.Create();
+        // Wrap the raw wire client so every operation on the device's single FOCAS/2 socket is
+        // serialized (request→response on one socket cannot interleave) and time-bounded. Without
+        // this, the equipment poll, fixed-tree loop, probe, and recycle loop collide on the shared
+        // socket and a stalled read blocks forever — leaving bound tags at BadWaitingForInitialData.
+        device.Client = new SynchronizedFocasClient(_clientFactory.Create(), _options.Timeout);
         try
         {
             await device.Client.ConnectAsync(device.ParsedAddress, _options.Timeout, ct).ConfigureAwait(false);