Merge review R6 fixes: numeric array writes converted element-wise (checked) to the node's element type, refusing out-of-range/fractional/NaN; array-to-scalar refusal scoped to Modbus/S7; Primary-verdict pre-join window documented + real MemberUp subscription test; passive LocalDb pair half drain-gated on its mesh partner

Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe

docs/drivers/Mqtt.md

@@ -363,9 +363,14 @@ Hence: bind the claim to a connection, and rebuild the connection on role change
 | Role unknown, no driver peer (single node) | open | `ONLINE` |
 
 The verdict comes from `PrimaryGatePolicy.ShouldServiceAsPrimary` via `IDriverPrimaryRoleSource`
-(`Core.Abstractions`), published by `DriverHostActor` on every redundancy snapshot and **sampled on a
-1-second timer** rather than evented — a process-singleton raising events at per-instance drivers
-outlives every driver it holds a reference to.
+(`Core.Abstractions`), published by `DriverHostActor` at host start, on every cluster membership change and on
+every redundancy snapshot, and **sampled on a 1-second timer** rather than evented — a process-singleton
+raising events at per-instance drivers outlives every driver it holds a reference to.
+
+> ⚠️ **"Driver peer present" is this node's own cluster view.** Before the node has joined, it sees no
+> members, which is the single-node row: a node cold-starting into a pair whose peer is already Primary
+> can open the claim until its join completes (seconds; up to the bootstrap guard's 25 s partner probe),
+> so both nodes may briefly hold it (review R6 MINOR-2).
 
 > **Accepted trade: a brief edge-visible `OFFLINE` during failover**, while the old Primary stands down
 > and the new one connects and republishes. That is a genuine state transition — for that window there