feat(opcuaclient): #676 follow-ups — endpoint rewrite, stall wire test, fast definitive-loss recovery

- Endpoint rewrite: the driver now connects to the configured host AND port (scheme
  match, advertised path kept) instead of the server-advertised URL — fixes NAT/port-map
  upstreams and lets an in-test proxy carry the session (SDK SelectEndpoint rule).
- TcpStallProxy + OpcUaClientDriverStallWireTests: the in-place blip (#670) is now
  wire-tested on loopback — one Bad, frozen read stamp, same session, identical value
  republished Good, a post-recovery change arrives, no source-time regression after
  the SDK's late backlog flush.
- Defect found by that test, fixed: a change published right after a stall rode a
  Publish response the SDK timed out and never republished, leaving the node Good on
  the pre-change value indefinitely. New trailing reconcile read (Timeout +
  KeepAliveInterval after recovery) publishes any Good value newer than the last
  accepted one, through the replay guard's mark.
- IDriverConnectionLossSource (Core.Abstractions): opt-in definitive-loss signal.
  DriverInstanceActor attaches in PreStart / detaches in PostStop and turns a raise
  into a disconnect only while Connected. OpcUaClient raises once per session on
  keep-alive BadSessionIdInvalid/BadSessionClosed/BadSessionNotActivated/
  BadServerHalted (measured: the SDK never re-opens a halted channel) or a dropped
  subscription; ambiguous codes stay with the #527 watchdog.
- Replay guard: one Information summary per recovery when the window closes
  ("dropped N late notifications across M refs"), with a timer so quiet
  subscriptions log it too.
- ReconnectPeriod deleted (options, AdminUI form, docs, tests); stored configs that
  carry reconnectPeriod still parse in the factory, probe and browser.
- Docs: OpcUaClient.md, DriverLifecycle.md, driver-specs.md, CLAUDE.md.

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Contracts/OpcUaClientDriverOptions.cs

@@ -101,12 +101,6 @@ public sealed record OpcUaClientDriverOptions
     /// <summary>Client-side keep-alive interval.</summary>
     public TimeSpan KeepAliveInterval { get; init; } = TimeSpan.FromSeconds(5);
 
-    /// <summary>
-    ///     Retained for config compatibility only — no longer used (Gitea #670). The driver has no in-driver reconnect
-    ///     handler; a lost session is recovered by the host's comms-loss watchdog re-initialising the driver.
-    /// </summary>
-    public TimeSpan ReconnectPeriod { get; init; } = TimeSpan.FromSeconds(5);
-
     /// <summary>
     ///     When <c>true</c>, the driver accepts any self-signed / untrusted server certificate.
     ///     Dev-only — must be <c>false</c> in production so MITM attacks against the opc.tcp