feat(historian): #674 HistoryUpdate posture — future-skew bound, Primary gate, SqlServer v1 accepted, QuestDB TTL pin

- HistoryUpdate items with SourceTimestamp > now + ServerHistorian:HistoryUpdateMaxFutureSkew
  (default 1 day, <=0 disables) => BadOutOfRange in the node manager (every backend, never sent);
  clock injected via OtOpcUaNodeManager.Clock (host TimeProvider).
- HistoryUpdate is Primary-only: off-Primary => BadInvalidState per node, after authorization,
  same IDriverPrimaryRoleSource verdict as the native-ack gate; HistoryRead ungated.
- SqlServer: base schema requirement back to v1; SupportsModifiedTrail (v>=2). On v1 with
  AutoCreateSchema=false: writes/reads/events/retention work, modified reads + HistoryUpdate =>
  BadHistoryOperationUnsupported with nothing sent, retention skips SampleModified, one Warning per boot.
- QuestDB integration test pinning wall-clock TTL (far-future row evicts only partitions older
  than the TTL by the wall clock), with a positive control.
- Docs: Historian.md, Configuration.md, security.md, CLAUDE.md (incl. QuestDB retry duplicates,
  #674.4 anonymous-readable trail with ACL off, #674.5 not implemented).

Co-Authored-By: Claude <noreply@anthropic.com>

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Historian.SqlServer/SqlServerSchemaBootstrapper.cs

@@ -15,15 +15,27 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.Historian.SqlServer;
 ///     SQL, so a missing schema (or a SQL outage) does not serialise every write, read and alarm event behind one
 ///     semaphore and one round-trip each.
 ///     With <c>AutoCreateSchema=false</c> it only verifies <c>MAX(Version) &gt;= </c><see cref="RequiredVersion"/>.
+///     <para><b>Schema v1 is accepted (Gitea #674).</b> A database at version 1 (no <c>SampleModified</c>) still serves
+///     live writes, raw / processed / at-time reads, alarm events and retention; only the Part 11 modification trail is
+///     unavailable — <see cref="SupportsModifiedTrail"/> is false, modified reads and HistoryUpdate report
+///     <c>BadHistoryOperationUnsupported</c> without touching SQL, and one Warning is logged per instance (= per boot: the
+///     provider shares one bootstrapper). Before #674 a v1 database refused EVERY historian call, continuous-historization
+///     drains included, until script 002 was applied by hand.</para>
 /// </summary>
 internal sealed partial class SqlServerSchemaBootstrapper
 {
     /// <summary>
-    ///     The schema version this build requires: 2 = <c>002_sample_modified.sql</c> (Part 11 modified-value
-    ///     history, Gitea #668). An existing v1 schema is upgraded in place on the next bootstrap when
-    ///     <c>AutoCreateSchema</c> is on; otherwise the script must be applied by hand.
+    ///     The schema version this build requires to serve at all: 1 = <c>001_initial.sql</c>. Gitea #674 lowered it from
+    ///     2 — a missing modification trail disables only the features that need it (<see cref="ModifiedTrailVersion"/>).
     /// </summary>
-    public const int RequiredVersion = 2;
+    public const int RequiredVersion = 1;
+
+    /// <summary>
+    ///     The schema version that carries the Part 11 modification trail: 2 = <c>002_sample_modified.sql</c> (Gitea #668).
+    ///     An auto-creating bootstrap always upgrades to it; with <c>AutoCreateSchema=false</c> the script must be applied by
+    ///     hand (and the node restarted — the verdict is taken once per instance).
+    /// </summary>
+    public const int ModifiedTrailVersion = 2;
 
     private const string LockResource = "OtOpcUaHistorianSchema";
     private const int LockTimeoutMs = 30_000;
@@ -34,6 +46,13 @@ internal sealed partial class SqlServerSchemaBootstrapper
     private readonly SemaphoreSlim _gate = new(1, 1);
     private readonly BootstrapFailureCache _failure; // guarded by _gate
     private volatile bool _ready;
+    private volatile bool _supportsModifiedTrail;
+
+    /// <summary>
+    ///     Whether the schema carries the Part 11 modification trail (version &gt;= <see cref="ModifiedTrailVersion"/>).
+    ///     Meaningful only after <see cref="EnsureAsync"/> has succeeded (false before). Taken once per instance.
+    /// </summary>
+    public bool SupportsModifiedTrail => _supportsModifiedTrail;
 
     /// <summary>Creates the bootstrapper.</summary>
     /// <param name="conn">Connection helper.</param>
@@ -99,6 +118,13 @@ internal sealed partial class SqlServerSchemaBootstrapper
             throw new HistorianSchemaMissingException(
                 $"Historian schema [{_conn.Schema}] is missing version {RequiredVersion} (found {v}) and AutoCreateSchema is false. " +
                 "Apply the docs/historian/sqlserver/NNN_*.sql scripts above version " + v + " in order, or enable AutoCreateSchema.");
+        _supportsModifiedTrail = v >= ModifiedTrailVersion;
+        if (!_supportsModifiedTrail)
+            _log.LogWarning("Historian schema [{Schema}] is at version {Version}, below {TrailVersion}, and AutoCreateSchema is false: " +
+                "the Part 11 modification trail is unavailable, so modified-value history reads and HistoryUpdate report " +
+                "BadHistoryOperationUnsupported and retention skips SampleModified. Live historization, reads, events and retention " +
+                "are unaffected. Apply docs/historian/sqlserver/002_sample_modified.sql and restart the node to enable them.",
+                _conn.Schema, v, ModifiedTrailVersion);
     }
 
     private async Task ApplyAsync(SqlConnection conn, CancellationToken ct)