Implement LmxOpcUa server — all 6 phases complete

Full OPC UA server on .NET Framework 4.8 (x86) exposing AVEVA System
Platform Galaxy tags via MXAccess. Mirrors Galaxy object hierarchy as
OPC UA address space, translating contained-name browse paths to
tag-name runtime references.

Components implemented:
- Configuration: AppConfiguration with 4 sections, validator
- Domain: ConnectionState, Quality, Vtq, MxDataTypeMapper, error codes
- MxAccess: StaComThread, MxAccessClient (partial classes), MxProxyAdapter
  using strongly-typed ArchestrA.MxAccess COM interop
- Galaxy Repository: SQL queries (hierarchy, attributes, change detection),
  ChangeDetectionService with auto-rebuild on deploy
- OPC UA Server: LmxNodeManager (CustomNodeManager2), LmxOpcUaServer,
  OpcUaServerHost with programmatic config, SecurityPolicy None
- Status Dashboard: HTTP server with HTML/JSON/health endpoints
- Integration: Full 14-step startup, graceful shutdown, component wiring

175 tests (174 unit + 1 integration), all passing.

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

gr/layout.md

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+# Galaxy Repository Object Layout
+
+## Object Hierarchy
+
+Galaxy objects are organized in a tree hierarchy. The root is the Galaxy itself (ZB), with objects nested under areas and other containers:
+
+```
+ZB (Galaxy)
+├── UnassignedArea
+├── DEV
+│   ├── DevAppEngine
+│   ├── DevPlatform
+│   └── TestArea [TestArea]
+│       └── DevTestObject
+│           ├── TestChildObject [TestChildObject]
+│           ├── TestMachine_001
+│           ├── DelmiaReceiver_001 [DelmiaReceiver]
+│           └── MESReceiver_001 [MESReceiver]
+```
+
+Objects have a **tag_name** (instance name, e.g. `TestMachine_001`) and optionally a **contained_name** shown in brackets (the template/type, e.g. `[DelmiaReceiver]`). Parent-child containment defines the deployment and organizational structure.
+
+## Contained Name vs Tag Name
+
+Each child object has a **contained_name** (its local name within its parent) and a globally unique **tag_name**. When browsing the hierarchy, we want to see the contained name path; when referencing tags at runtime, the tag_name is used.
+
+| Hierarchy Path (contained names) | Tag Reference (tag_name) |
+|----------------------------------|--------------------------|
+| `TestMachine_001.DelmiaReceiver.DownloadPath` | `DelmiaReceiver_001.DownloadPath` |
+| `TestMachine_001.MESReceiver.MoveInBatchID` | `MESReceiver_001.MoveInBatchID` |
+
+The contained_name (`DelmiaReceiver`) is the human-readable name scoped to its parent, while the tag_name (`DelmiaReceiver_001`) is the system-assigned globally unique name. Translation between the two is needed when going from a hierarchy browse to tag-level data access.
+
+## Target OPC UA Server Structure
+
+The OPC UA server should mirror the Galaxy hierarchy using contained names for folder/container structure. Attributes appear as tags within their object's container, and child objects appear as sub-containers. When an OPC UA client reads/writes a tag value, the contained name path is translated to the tag_name reference.
+
+```
+ZB/
+└── DEV/
+    └── TestArea/
+        └── TestMachine_001/
+            ├── MachineID              → reads/writes TestMachine_001.MachineID
+            ├── MachineCode            → reads/writes TestMachine_001.MachineCode
+            ├── DelmiaReceiver/
+            │   ├── DownloadPath       → reads/writes DelmiaReceiver_001.DownloadPath
+            │   ├── JobStepNumber      → reads/writes DelmiaReceiver_001.JobStepNumber
+            │   ├── PartNumber         → reads/writes DelmiaReceiver_001.PartNumber
+            │   └── RecipeDownloadFlag → reads/writes DelmiaReceiver_001.RecipeDownloadFlag
+            └── MESReceiver/
+                ├── MoveInBatchID      → reads/writes MESReceiver_001.MoveInBatchID
+                ├── MoveInCompleteFlag → reads/writes MESReceiver_001.MoveInCompleteFlag
+                ├── MoveInFlag         → reads/writes MESReceiver_001.MoveInFlag
+                └── ...
+```
+
+Folders (ZB, DEV, TestArea) are structural — they organize the browse tree but don't have tags. Containers (TestMachine_001, DelmiaReceiver, MESReceiver) hold both attributes (tags) and potentially child containers.
+
+## Tag (Attribute) View
+
+Tags represent the data attributes exposed by objects. They are referenced in a flattened dot-notation format using the tag_name:
+
+```
+<tag_name>.<AttributeName>
+```
+
+Examples:
+- `TestMachine_001.MachineID`
+- `TestMachine_001.MachineCode`
+- `MESReceiver_001.MoveInBatchID`
+- `MESReceiver_001.MoveInCompleteFlag`
+- `MESReceiver_001.MoveInJobSequenceNumber`
+- `DelmiaReceiver_001.DownloadPath`
+- `DelmiaReceiver_001.JobStepNumber`
+- `DelmiaReceiver_001.PartNumber`
+- `DelmiaReceiver_001.RecipeDownloadFlag`
+
+This flat view collapses the hierarchy — all attributes across all objects appear as `tag_name.AttributeName` regardless of where the object sits in the containment tree.