Tracking: unsupported jsonata language features surfaced by the 2.2.1 test corpus #439

Tracking issue for jsonata language features that JSONata4Java does not yet support, surfaced while comparing against the jsonata-js 2.2.1 test corpus during the Jackson 3 migration (#430 / PR #431).

These are language/grammar gaps (not simple function bugs) — each likely needs grammar and/or evaluator work. Filed as a single tracking issue rather than one-per-case since they are related "not-yet-implemented" gaps vs the reference (try.jsonata.org 2.2.1).

1. Inline lambda type signatures

Lambda definitions with a type signature are not parsed:

λ($a, $b)<n+n:o>{ ... }

Corpus: function-signatures/case035–case040 (6 cases).

2. ~> function application followed by trailing []

Chained function application with a trailing array-selector is not handled:

$data ~> $map($square)[]

Corpus: higher-order-functions / hof-map case0011.

3. Array-sequence construction with trailing []

Nested-array / sequence-construction semantics of a trailing [] on a path/array constructor:

$.[value, epochSeconds][]

Expected: force the result into a sequence/array per 2.2.1 semantics.

Reference: jsonata-js 2.2.1. Scope note: these are intentionally out of scope for the Jackson 3 migration PR (#431); this issue captures them for a future compatibility effort.