JVNAUTOSCI-2688: Normalise structural predicate extent filters

[witbrock]

Outcome

Structural predicate concept IDs such as #V#is_an_instance_of now resolve to the canonical relationship storage key before predicate-extent reads. Namespaced and bare structural filters therefore return the same relationship set, while ordinary namespaced predicates remain unchanged.

Scope

• add one Vontology-backed structural predicate storage-key resolver
• apply it at the shared extent-index boundary and both predicate/concept relationship routes
• retain requested predicate IDs in predicate-route response presentation
• cover the motivating Zhenyun-style incoming and outgoing relationship case

Validation

• 69 passed, 3 deselected across the four affected backend test modules
• the three deselected unrelated route tests fail identically on untouched origin/main
• six narrow regressions passed before the broader run
• changed modules compile
• ruff check --select F,E9 passes
• git diff --check passes

No deployment or live-service restart is included.