fix(opctreemanager): resolve OpcFbPath exactly

[mrcsin]

Summary

GetProtocol took the configured OpcFbPath, and when no OPC UA FB node sat there it stripped the last segment and searched the parent, up to the tree root. A path naming a child of the FB node, or any path with a wrong segment in the middle, silently resolved to an ancestor: the module then worked against a node the operator never wrote, and the log reported that node rather than the setting. A wrong first segment walked to the root and failed with or any of its ancestors, which says nothing about where the path went wrong.

The operator names the node directly in the property grid, so the path is now taken as written. A miss fails with No OPC UA FB node at path 'X'. OpcFbPath must name the OPC UA FB node itself.

No new setting and nothing to fill in differently: OpcFbPath is the same property, with the same default Система.АРМ.OPC UA Siemens. Only the behaviour on a wrong value changes.

Type of change

• fix — bug fix

Changes

• GetProtocol takes a Func<string, ITreeItemHlp?> resolver instead of IProjectHlp, matching the seam already used by TreeReshaper, PlanExecutor and ProjectSubtreeDisconnector. That is what makes the refusal testable.
• the property description in the FB says the path must name the node itself

Changes touching FB code

• XML pin IDs match the const int *PinId constants in the FB class
• New runtime-only fields carry [NonSerialized]
• [ComVisible(true)] + [Guid] untouched on existing FBs
• Read Docs/architecture/masterscada-fb-primer.md and Docs/architecture/architecture.md
• Checked Docs/known_issues/

Testing

• dotnet build NtoLib.sln — 0 errors, 0 warnings
• dotnet test NtoLib.sln — 373 passed
• dotnet format NtoLib.sln --verify-no-changes — exit 0
• Manual host smoke 2026-09-22 with a correct path: group resolved, 23 nodes constructed

GetProtocol_PathBelowTheFbNode_Fails asserts the refusal sentence, not just IsFailed. Verified by experiment: reinstating the ancestor walk restores the old behaviour and the test goes red. Asserting IsFailed alone did not discriminate, because the walk found the node and then failed later on Instance is null.