Add CQL2 array predicates, cql-json \ e\ support, and parser validation

[Nortaq-PlayNexus]

Closes #19, #47, #144, #160

Changes

cql2_text: array predicates (#160)
A_EQUALS, A_CONTAINS, A_CONTAINEDBY, and A_OVERLAPS are now supported, with either an array literal (('a', 'b', 'c')) or an attribute on the right-hand side, matching the CQL2 spec. Previously A_CONTAINS('values', ('a', 'b', 'c')) raised a LALR error (KeyError: 'COMMA').

• parsers/cql2_text/grammar.lark: added array_predicate and array_literal rules
• parsers/cql2_text/parser.py: added binary_array_predicate and array_literal transformer methods using the existing ARRAY_PREDICATES_MAP

cql2_text: single-character attribute names (#144)
The attribute terminal regex used +, so names like a could not be parsed. Changed to * ([a-zA-Z][a-zA-Z_:0-9.]*) so a = 1 parses correctly.

cql-json: ne comparison operator (#19)
{"ne": [...]} now produces ast.NotEqual, completing the CQL2 comparison operator set for the JSON parser.

cql-json: malformed-expression validation (#47)

• Nodes with more than one predicate key (e.g. {"and": [...], "or": [...]}) now raise ValueError("multiple predicates ...") instead of silently picking one.
• and/or with fewer than 2 operands now raise ValueError("at least 2 operands") instead of producing a wrong AST.

Testing

• 11 new tests across tests/parsers/cql2_text/test_parser.py and tests/parsers/cql_json/test_parser.py
• 294 passed locally (tests/parsers, tests/native, tests/test_utils.py)
• ruff check clean on all changed Python files