test: Add 13 extended-parameter-type conformance fixtures

[leongdl]

Summary

13 extended-parameter-type fixtures from a coverage audit of RFC 0007. Suite: EXPR 350 → 363 passing, 0 failing; base unchanged.

Areas covered

• int64 accept twins on list element types: LIST[INT] element and LIST[LIST[INT]] inner element at 2^63−1 accepted — the data-axis boundary the audit found untested for every container type.
• First-ever LIST[BOOL] runtime coverage (the audit found EXPR/jobs/ had no 2.15--* file at all): element values reaching the task, and interpolation rendering. Note: these two fixtures pass on openjd-rs and currently FAIL on the Python CLI (TypeError: List contains incompatible types: bool, string) — they are live divergence catchers, green against the reference implementation.
• Mixed-case type spellings: LiSt[iNt] and friends accepted with EXPR (job parameters).
• Normative prohibitions: BOOL + allowedValues rejected; item: on LIST[BOOL] rejected; LIST[LIST[LIST[INT]]] triple nesting rejected — all stated in the schema, none previously tested.
• LIST[PATH] element constraints: item.allowedValues accept + violation pair (previously appeared in zero fixtures).
• Indexed-element property access: {{Param.Paths[0].stem}} — the subscript route of the known property-access bug class; verified NOT affected.
• RANGE_EXPR endpoint overflow reject and a LIST[STRING] wrong-item-type negative (numeric elements rejected, no silent YAML coercion — verified on both implementations).

Companion PR

Five spec-correct fixtures that FAIL today (list-element 2^63 acceptance in both implementations, the openjd-rs 2^62 endpoint cap, task-parameter case-insensitivity unimplemented in both, base lowercase type acceptance in openjd-rs) are in the expected-failures PR (branch conformance-param-types-expected-failures).