Reject unknown type names inside containers

[Hakaou]

Closes #589, the second point of the suggested fix in #571. Draft until #575 lands: this branch is stacked on it because it needs the Nested node, so the first commit here is #575's and only the last one belongs to this PR.

Summary

ValidateAST only looked at the root of a type name. Inside Array, Nullable, Tuple, Map, LowCardinality or Nested, a name the parser does not know became a Void terminal, the column was created as ColumnNothing, and the block was read one byte per row without any error. CreateColumnByType("Array(Int256)") returned a column typed Array(Void), and SELECT [CAST(1, 'Int256')] returned a row of wrong data.

Behavior changes

• The elements of those six containers are validated. A client now gets unsupported column type: Array(Int256) instead of wrong data, the same error it already gets for Int256 at the root. Other names this applies to, all seen in toTypeName on 26.11: Variant, Dynamic, BFloat16, UInt256, the Interval* types, LineString, MultiPoint, QBit, AggregateFunction.
• The arguments of every other type are left alone: the settings and typed paths of JSON(max_dynamic_paths=1, a Int256, SKIP b) keep decoding as before, and the function name of SimpleAggregateFunction(anyLast, LowCardinality(String)) is not a type.
• Nothing, which the server sends for SELECT [] and SELECT NULL, is registered as the type it already was by accident, so those queries keep working.
• Reject wrapper types built over unsupported nested types #578 covers the neighbouring case of a known name the factory cannot build inside a wrapper. The two change different functions and merge independently.

Tests

• type_parser_ut: a parametrised test with a fresh AST per case, six unknown names inside containers rejected, Nothing, SimpleAggregateFunction, parameterised JSON, Enum8 and DateTime64 accepted.
• CreateColumnByType_ut: Array(Int256) and Array(Nested(key String, value Dynamic)) give nullptr, Array(Nothing), Nullable(Nothing) and parameterised JSON give a column.
• client_ut, both fixtures: SELECT [] AS empty, NULL AS null_value, [NULL] AS nulls decodes, SELECT [CAST(1, 'Int256')] throws UnimplementedError, and CAST('{"a":1}', 'JSON(max_dynamic_paths=1)') reads back {"a":1} with output_format_native_write_json_as_string = 1.

Full suite green locally (macOS arm64, Apple clang 21) against ClickHouse 26.11.1 master build, the new tests also against 25.12 and 26.3. Parser, factory, types and client suites pass under AddressSanitizer and UBSan.

Open question

Inside a container, should an unknown name make CreateColumnByType return nullptr, as it does at the root, or would you rather have an exception naming the inner type? The tests hold either way, only the end of ValidateAST would change.