docs(phase4b): Modbus driver-type canonical + Galaxy nesting + FOCAS auto-scale (managed-backend caveat)

docs/v2/config-db-schema.md

@@ -241,7 +241,7 @@ CREATE TABLE dbo.DriverInstance (
     ClusterId               nvarchar(64)        NOT NULL FOREIGN KEY REFERENCES dbo.ServerCluster(ClusterId),
     NamespaceId             nvarchar(64)        NOT NULL FOREIGN KEY REFERENCES dbo.Namespace(NamespaceId),
     Name                    nvarchar(128)       NOT NULL,
-    DriverType              nvarchar(32)        NOT NULL,   -- Galaxy | ModbusTcp | AbCip | AbLegacy | S7 | TwinCat | Focas | OpcUaClient
+    DriverType              nvarchar(32)        NOT NULL,   -- Galaxy | Modbus | AbCip | AbLegacy | S7 | TwinCat | Focas | OpcUaClient
     Enabled                 bit                 NOT NULL DEFAULT 1,
     DriverConfig            nvarchar(max)       NOT NULL CHECK (ISJSON(DriverConfig) = 1)
 );
@@ -259,7 +259,7 @@ CREATE UNIQUE INDEX UX_DriverInstance_Generation_LogicalId
 | `DriverType` | Allowed `Namespace.Kind` |
 |--------------|--------------------------|
 | Galaxy | SystemPlatform |
-| ModbusTcp / AbCip / AbLegacy / S7 / TwinCat / Focas | Equipment |
+| Modbus / AbCip / AbLegacy / S7 / TwinCat / Focas | Equipment |
 | OpcUaClient | Equipment OR SystemPlatform (per-instance config decides) |
 
 **Same-cluster invariant** (revised after adversarial review 2026-04-17 finding #1): the `Namespace` referenced by `DriverInstance.NamespaceId` MUST belong to the same `ClusterId`. This is a cross-cluster trust boundary — without enforcement, a draft for cluster A could bind to a namespace owned by cluster B, leaking that cluster's URI into A's endpoint and breaking tenant isolation. Three layers of enforcement:
@@ -801,7 +801,7 @@ Examples of the per-driver shapes — full specs in `driver-specs.md`:
   "Historian": { "Enabled": false }
 }
 
-// DeviceConfig for DriverType=ModbusTcp
+// DeviceConfig for DriverType=Modbus
 {
   "Host": "10.0.3.42",
   "Port": 502,
@@ -810,7 +810,7 @@ Examples of the per-driver shapes — full specs in `driver-specs.md`:
   "AddressFormat": "Standard"   // or "DL205"
 }
 
-// TagConfig for DriverType=ModbusTcp
+// TagConfig for DriverType=Modbus
 {
   "RegisterType": "HoldingRegister",
   "Address": 100,