feat(historian-gateway): wire ContinuousHistorizationRecorder into DI + hosted lifecycle + meters

Bind ContinuousHistorizationOptions (Enabled/OutboxPath/CommitMode/
CommitIntervalMs/DrainBatchSize/DrainIntervalSeconds/Capacity/backoff) with a
warn-only Validate(); gated on Enabled AND the ServerHistorian gateway being
configured, the Host registers the durable FasterLogHistorizationOutbox (container
-disposed) + a gateway-backed GatewayHistorianValueWriter, and binds outbox
depth/dropped observable gauges on the central scraped meter. WithOtOpcUaRuntimeActors
spawns the recorder (over the same dependency-mux ref) when the options + writer +
outbox resolve, registering ContinuousHistorizationRecorderKey. Spawned with an EMPTY
historized-ref set: the deployed address space builds later, so ref population is a
documented follow-on (a later SetHistorizedRefs feed) — T18 wires the actor + outbox
+ writer + meters; the ref feed is the known remaining gap.

Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Historian/ContinuousHistorizationOptions.cs

@@ -0,0 +1,83 @@
+using System.Collections.Generic;
+
+namespace ZB.MOM.WW.OtOpcUa.Runtime.Historian;
+
+/// <summary>
+///     Binds the <c>ContinuousHistorization</c> configuration section that gates the continuous
+///     historization of driver (non-Galaxy) tag values. When <see cref="Enabled"/> is <c>true</c>
+///     <em>and</em> the <c>ServerHistorian</c> gateway is configured, the Host builds a durable,
+///     crash-safe <c>FasterLogHistorizationOutbox</c> + a gateway-backed <c>IHistorianValueWriter</c>
+///     and <c>WithOtOpcUaRuntimeActors</c> spawns the <see cref="ContinuousHistorizationRecorder"/>;
+///     otherwise no recorder is spawned and driver tag values are not historized.
+///     <para>
+///         The recorder taps the per-node dependency-mux value fan-out, appends each numeric value to
+///         the outbox (the crash boundary), and drains the outbox to the historian's SQL live-value
+///         write path (<c>WriteLiveValues</c>) through the single <c>ServerHistorian</c> gateway. The
+///         gateway connection (endpoint / key / TLS) is sourced from <c>ServerHistorianOptions</c> — this
+///         section carries only the recorder + outbox knobs, never a gateway address or credential.
+///     </para>
+/// </summary>
+public sealed class ContinuousHistorizationOptions
+{
+    /// <summary>The configuration section name this options class binds.</summary>
+    public const string SectionName = "ContinuousHistorization";
+
+    /// <summary>
+    ///     When <c>true</c> (and the <c>ServerHistorian</c> gateway is configured), the
+    ///     continuous-historization recorder + its durable outbox are wired and spawned; when
+    ///     <c>false</c> (the default) no recorder is spawned and driver tag values are not historized.
+    /// </summary>
+    public bool Enabled { get; init; }
+
+    /// <summary>
+    ///     Directory holding the FasterLog outbox segment + commit files. Required when
+    ///     <see cref="Enabled"/> is <c>true</c>. In production set an <b>absolute</b> path on durable
+    ///     storage — a relative path resolves against the host's working directory, which may change
+    ///     across deployments.
+    /// </summary>
+    public string OutboxPath { get; init; } = "";
+
+    /// <summary>
+    ///     Outbox commit cadence: <c>PerEntry</c> (the default) fsyncs the log before each append
+    ///     returns (safest, no loss window); <c>Periodic</c> batches commits onto a background timer
+    ///     every <see cref="CommitIntervalMs"/> ms (higher throughput, a bounded worst-case loss window).
+    ///     Parsed case-insensitively against <c>HistorizationCommitMode</c>; an unrecognized value falls
+    ///     back to <c>PerEntry</c>.
+    /// </summary>
+    public string CommitMode { get; init; } = "PerEntry";
+
+    /// <summary>Periodic-mode commit cadence in milliseconds; must be positive when
+    /// <see cref="CommitMode"/> is <c>Periodic</c>. Ignored under <c>PerEntry</c>.</summary>
+    public int CommitIntervalMs { get; init; } = 100;
+
+    /// <summary>Maximum outbox entries peeked + written per drain pass; clamped to a positive value by
+    /// the recorder (a non-positive value falls back to 64).</summary>
+    public int DrainBatchSize { get; init; } = 64;
+
+    /// <summary>Steady drain cadence in seconds (also the post-success reschedule). Defaults to 2.</summary>
+    public double DrainIntervalSeconds { get; init; } = 2;
+
+    /// <summary>Maximum un-acked outbox entries before the drop-oldest capacity policy kicks in;
+    /// <c>0</c> (the default) means unbounded.</summary>
+    public int Capacity { get; init; }
+
+    /// <summary>Initial retry backoff (seconds) after a failed drain pass. Defaults to 1.</summary>
+    public double MinBackoffSeconds { get; init; } = 1;
+
+    /// <summary>Cap (seconds) on the exponential retry backoff after repeated drain failures. Defaults to 30.</summary>
+    public double MaxBackoffSeconds { get; init; } = 30;
+
+    /// <summary>Returns operator-facing misconfiguration warnings for an <c>Enabled</c> recorder
+    /// (empty when disabled or correctly configured). Pure — the registration logs each entry.</summary>
+    /// <returns>Zero or more human-readable warning messages (never carrying secret values).</returns>
+    public IReadOnlyList<string> Validate()
+    {
+        var warnings = new List<string>();
+        if (!Enabled) return warnings;
+        if (string.IsNullOrWhiteSpace(OutboxPath))
+            warnings.Add("ContinuousHistorization:OutboxPath is empty while historization is enabled — the durable outbox has no directory to persist to; the recorder cannot be wired.");
+        if (string.Equals(CommitMode, "Periodic", StringComparison.OrdinalIgnoreCase) && CommitIntervalMs <= 0)
+            warnings.Add($"ContinuousHistorization:CommitIntervalMs is {CommitIntervalMs} — must be > 0 in Periodic commit mode; the periodic-commit loop cannot run.");
+        return warnings;
+    }
+}