fix(agent): reject non-UUID AgentUuid on override + persisted paths

[ottobolyos]

Summary

Hardens the Agent meta-device UUID resolution slice added by #168 so malformed input never reaches the wire — closing the gap on both the operator-supplied override AND the persisted agent.information.json paths. The prior single-path validation left Path 2 open: a corrupted state file (or a pre-hardening agent version that wrote non-UUID content) would flow straight to the wire and fail every downstream MTConnect Part 1 XSD-validating consumer on typed enum/decimal DataItems.

Standard interpretation — XMI vs XSD ambiguity

The MTConnect standard is not internally consistent on whether the uuid attribute must be a strict RFC 4122 / ISO 11578 UUID or an arbitrary non-empty string. This PR adopts the XMI/SysML interpretation. Both source-of-truth citations:

XMI/SysML glossary (strict-UUID reading) — build/sysml-model/MTConnectSysMLModel.xml, glossary enumeration literal UUID (xmi:id='_19_0_3_68e0225_1605548124036_660108_342'):

universally unique identifier as specified in ISO 11578 or RFC 4122.

XSD (permissive-string reading) — tests/Compliance/MTConnect-Compliance-Tests/Schemas/v2_7/MTConnectDevices_2.7.xsd, simpleType UuidType:

<xs:simpleType name='UuidType'>
  <xs:annotation>
    <xs:documentation>
      A universally unique id that uniquely identifies the element for
      it's entire life
    </xs:documentation>
  </xs:annotation>
  <xs:restriction base='xs:string'/>
</xs:simpleType>

xs:string with no pattern facet — schema-valid for any non-empty string. The field-level documentation on Device.uuid in the same XSD reinforces the permissive reading:

The components universally unique id. This can be composed of the manufactures id or name and the serial number.

Rationale for choosing XMI-strict: the XMI glossary is the normative source in the MTConnect-Standard sysml-first pipeline (XSDs are generated from the SysML model, not the other way around), and RFC 4122 canonical UUIDs are a superset of every reasonable operator-authored identifier scheme — an operator whose in-house scheme is <manufacturer>-<serial> can trivially derive a stable UUID v5 from it, but a downstream consumer parsing a bare string can't tell whether it's meant to be a UUID or something else. Rejecting non-UUID on the wire preserves the safer contract for consumers.

Open question for the maintainer: if the XSD-permissive reading is deliberate (i.e. the standard truly means "any string that's unique enough for your deployment"), this PR is over-strict and the fix should instead be a validation warning + pass-through, not a rejection. Please confirm intent before merge.

Change

• New AgentUuidResolver.Resolve (public static, MTConnect.NET-Common) implements the three-path algorithm:
  • Path 1 — validated operator override wins;
  • Path 2 — validated persisted state wins over derivation;
  • Path 3 — deterministic UUID v5 derivation from ServiceName.
    Malformed input on Path 1 OR Path 2 logs a warning via a delegate hook (so MTConnect.NET-Common takes no hard dependency on NLog) and falls through to the next path. Raw values echoed to the warn log are pre-sanitized (CRLF stripped, truncated to 64 chars) as guards against log-injection and paste-in-wrong-field secret leakage.
• MTConnectAgentApplication.RunAgent routes through the shared resolver instead of hand-rolling the dual-if resolution. Collapses the two-branch shape that re-tested string.IsNullOrEmpty twice.
• DeterministicAgentUuid.TryValidate parameter renamed normalised → normalized (American English spelling is used throughout committed code); XML-doc verbs updated to match. Positional / out var callers unaffected.
• Test fixtures brought forward — AgentUuidConfigOverrideTests + AgentUuidLongitudinalInvariantsTests now route their boot simulation through AgentUuidResolver.Resolve instead of inline replay, and their fixture literals are canonical RFC 4122 UUIDs (previously non-UUID strings that survived only because the inline replay omitted TryValidate — fake-green). Every fixture marked [NonParallelizable] with orphan-.bak.* sweep.

Depends on

• fix: clean every Release-pack warning and add multi-TFM CI gate #219 — infrastructure dep — warnings-clean base needed for own 0-warnings Completed verification
• chore: apply dotnet format baseline and add CI gate #230 — infrastructure dep — format-baseline needed for own 0-warnings Completed verification