This PR implements the **OPC UA Device Integration (DI, OPC 10000-100)**
companion-spec library trio (`Opc.Ua.Di` / `Opc.Ua.Di.Server` /
`Opc.Ua.Di.Client`) plus a worked example
(`Applications/MinimalPumpServer`) demonstrating the OPC 40223 Pumps
companion specification end-to-end with full simulation. It also closes
11 fluent-API gaps in `Opc.Ua.Server.Fluent`, three source-generator
bugs, integrates the DI layer into the unified `services.AddOpcUa()`
Microsoft.Extensions DI hosting pattern, and adds 250+ new tests.
**Worked example — `Applications/MinimalPumpServer/`**
- AOT-compatible console host using `Host.CreateApplicationBuilder` +
`AddOpcUa()`.
- `PumpNodeManager` inherits from `DiNodeManager`; multi-namespace (DI +
Machinery + Pumps) via runtime NodeSet2 loading and
`ModelLoaderBuilder`.
- Demonstrates declarative second-pump creation via
`.ConfigureDevicesFor<PumpNodeManager>(...)` and software-package
seeding from the same configurator.
- Full simulation: pressure, temperatures, power, flow, efficiency,
level, cavitation/overheat fault injection, alarm setup, NAMUR-style
supervision.
**Documentation**
- `Docs/Opc.Ua.Di/` — README, DeviceBuilder, Hosting, LockService,
SoftwareUpdate, ClientHelpers (6 new developer guides).
- `Docs/Opc.Ua.Di/ComplianceMatrix.md` — every DI declaration mapped to
In-v1 / Generated / Deferred / Excluded.
- `Docs/CompanionSpecLibraries.md` — packaging guide for new
companion-spec libraries.
- `Docs/FluentApiGaps.md` — historical record of G1–G11.
- `Docs/SourceGeneratedNodeManagers.md` updated for richer node
managers.
- `Docs/plans/StateMachineBuilder.md` — deferred state-machine builder
design.
Generate stack and application code using source generators
Change built in types to readonly structs
Update localized text implementation to use JSON text serializer
Status code with symbolic names
Immutable node ids
No boxing for all built in types <= 8 bytes in Variant.
Split user identity token and token handling via token handler
Add migration guide for breaking changes
Marc Schier