Add Galaxy platform scope filter so multi-node deployments can restrict the OPC UA address space to only objects hosted by the local platform, reducing memory footprint and MXAccess subscription count from the full Galaxy (49 objects / 4206 attributes) down to the local subtree (3 objects / 386 attributes on the dev Galaxy).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docs/Configuration.md

@@ -88,6 +88,8 @@ Controls the Galaxy repository database connection used to build the OPC UA addr
 | `ChangeDetectionIntervalSeconds` | `int` | `30` | How often the service polls for Galaxy deploy changes |
 | `CommandTimeoutSeconds` | `int` | `30` | SQL command timeout for repository queries |
 | `ExtendedAttributes` | `bool` | `false` | Load extended Galaxy attribute metadata into the OPC UA model |
+| `Scope` | `GalaxyScope` | `"Galaxy"` | Controls how much of the Galaxy hierarchy is loaded. `Galaxy` loads all deployed objects (default). `LocalPlatform` loads only objects hosted by the platform deployed on this machine. See [Galaxy Repository — Platform Scope Filter](GalaxyRepository.md#platform-scope-filter) |
+| `PlatformName` | `string?` | `null` | Explicit platform hostname for `LocalPlatform` filtering. When null, uses `Environment.MachineName`. Only used when `Scope` is `LocalPlatform` |
 
 ### Dashboard
 
@@ -242,6 +244,7 @@ Three boolean properties act as feature flags that control optional subsystems:
 - **`OpcUa.AlarmFilter.ObjectFilters`** -- List of wildcard template-name patterns that scope alarm tracking to matching objects and their descendants. An empty list preserves the current unfiltered behavior; a non-empty list includes an object only when any name in its template derivation chain matches any pattern, then propagates the inclusion to every descendant in the containment hierarchy. `*` is the only wildcard, matching is case-insensitive, and the Galaxy `$` prefix on template names is normalized so operators can write `TestMachine*` instead of `$TestMachine*`. Each list entry may itself contain comma-separated patterns (`"TestMachine*, Pump_*"`) for convenience. When the list is non-empty but `AlarmTrackingEnabled` is `false`, the validator emits a warning because the filter has no effect. See [Alarm Tracking](AlarmTracking.md#template-based-alarm-object-filter) for the full matching algorithm and telemetry.
 - **`Historian.Enabled`** -- When `true`, the service calls `HistorianPluginLoader.TryLoad(config)` to load the `ZB.MOM.WW.LmxOpcUa.Historian.Aveva` plugin from the `Historian/` subfolder next to the host exe and registers the resulting `IHistorianDataSource` with the OPC UA server host. Disabled by default because not all deployments have a Historian instance -- when disabled the plugin is not probed and the Wonderware SDK DLLs are not required on the host. If the flag is `true` but the plugin or its SDK dependencies cannot be loaded, the server still starts and every history read returns `BadHistoryOperationUnsupported` with a warning in the log.
 - **`GalaxyRepository.ExtendedAttributes`** -- When `true`, the repository loads additional Galaxy attribute metadata beyond the core set needed for the address space. Disabled by default to minimize startup query time.
+- **`GalaxyRepository.Scope`** -- When set to `LocalPlatform`, the repository filters the hierarchy and attributes to only include objects hosted by the platform whose `node_name` matches this machine (or the explicit `PlatformName` override). Ancestor areas are retained to keep the browse tree connected. Default is `Galaxy` (load everything). See [Galaxy Repository — Platform Scope Filter](GalaxyRepository.md#platform-scope-filter).
 
 ## Configuration Validation
 
@@ -319,7 +322,9 @@ Integration tests use this constructor to inject substitute implementations of `
     "ConnectionString": "Server=localhost;Database=ZB;Integrated Security=true;",
     "ChangeDetectionIntervalSeconds": 30,
     "CommandTimeoutSeconds": 30,
-    "ExtendedAttributes": false
+    "ExtendedAttributes": false,
+    "Scope": "Galaxy",
+    "PlatformName": null
   },
   "Dashboard": {
     "Enabled": true,