Fix copy-paste errors and stale metadata in Hydra models

[tomcrane]

Small copy-paste and metadata fixes in the Hydra model layer and the custom-header feature. None of these change consumer-facing runtime JSON values — they affect generated vocab/Hydra documentation, one validation error message, and property emission order only. One commit per fix.

• CustomHeader.Role was declared ReadOnly = true in its [HydraLink] attribute, but role is freely settable on POST and PUT (the converter copies it and UpdateCustomHeader writes it). Now ReadOnly = false to match behaviour.
• Custom-header validator/converter said "named query" — the "@id must not be supplied" rule reported "DLCS must allocate named query id..." on a custom header request, and the converter's parameter was named hydraNamedQuery. Both are copy-paste remnants from the NamedQuery feature; message and parameter renamed.
• Tied JsonProperty Orders made emission order undefined for several properties: ImageStorage had adjunctSize/lastChecked/checkingInProgress all at Order 55 (now 55/56/57); ApiKey had key/secret both at 12 (now 12/13); PortalUser had created/roles both at 13 (now 13/14, with enabled bumped 14→15 to preserve the sequence).
• QueueSummary vocab wiring was a copy-paste bug: the class was annotated [HydraClass(typeof(QueueClass), ...)] — pointing at the customer Queue's Hydra class rather than its own — and QueueSummaryClass bootstrapped over typeof(QueueSummaryClass) (itself) instead of typeof(QueueSummary). Both now follow the pattern used by Batch/BatchClass and Queue/QueueClass. Runtime JSON (the counts) is unaffected; the generated vocab/ApiDocumentation for QueueSummary was wrong.
• NamedQuery carried stale metadata: the class was still annotated [Unstable(Note = "Currently the named query implementation is a placeholder,")] although the named-query management API (GET/PUT/DELETE/POST) and all output projections are fully implemented; and DefineOperations advertised a PATCH operation the controller does not implement. Annotation removed, PATCH dropped from the advertised operations.

Noticed while in NamedQuery.cs but deliberately not changed here: global and template share JsonProperty Order 11 — the same defect class as the renumbering above, left for a follow-up.

Builds clean against develop (0 errors).

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