test(gen-shacl): cover nested range_expression postconditions

[jdsika]

Test-only follow-up to #20 (mirror of linkml#3990). #20's composed translation handles a range_expression postcondition with the same code it uses for preconditions, but its tests covered nested postconditions only in a closed world. This PR pins the nested-postcondition cases:

Case	Expected	Checked against
open_world, wrapper omitted or empty	conforms	JSON Schema
open_world, value doesn't match	violation	JSON Schema
closed world, empty wrapper	conforms (the inner condition holds for an absent inner slot)	JSON Schema
multivalued wrapper, one member fails	violation (every member must satisfy it)	JSON Schema
enum value with a meaning	compared as that IRI, resolved on the range class	pyshacl, with explicit expectations, because the JSON-LD context renders this enum as strings (#40)
condition on the range class's identifier	rule skipped with a warning	the warning

The JSON Schema cases run for the declaring class and for a subclass. Four mutants of the shared code are each killed by the new cases: the inner presence default flipped, open_world ignored, the identifier check removed, and enum meaning ignored. No code changes.

History: this PR first implemented the translation itself, using an existential query form, so it had to skip multivalued wrappers and optional or multivalued inner slots. #20 now translates those cases. On this PR's original schemas, SHACL and JSON Schema agree on all 15 instances checked. The original commit is replaced by this test-only commit.

Fork stack: #19 → #20 → #35 (tests); #23 (docs) is also based on #20.

[jdsika]

Update: reopened as a test-only follow-up on #20 (see the description).

#20 (mirror of linkml#3990, head c89faac) supersedes this PR's original implementation. Its composed translation handles nested range_expression postconditions in general:

• 26 of this PR's original 32 tests pass on feat(gen-shacl): add a compositional fallback for rule-to-SPARQL conversion #20 without this PR's code. They include the linkml.validator parity matrix with open_world, nested numeric bounds, enum resolution on the range class, and the nested identifier skip.
• The other 6 asserted skips: multivalued wrappers, optional or multivalued inner slots, required combined with range_expression, and inherited multivalued attributes. The skips existed only because the existential query form couldn't express "every value". feat(gen-shacl): add a compositional fallback for rule-to-SPARQL conversion #20 translates these cases, and on this PR's own schemas SHACL and JSON Schema agree on all 15 instances checked.