fix(rowbinary): support compiling empty Tuple() type AST

[sidsri14]

Summary

Resolves the AST compilation failure for empty tuples (Tuple()) in @clickhouse/rowbinary.

Background & Root Cause

When @clickhouse/datatype-parser parses an empty tuple type string (such as Tuple() or Tuple(Tuple())), it returns a node with kind: NodeKind.DataType and name: "Tuple" (rather than NodeKind.TupleDataType which is returned for multi-element tuples like Tuple(UInt8, String)).

In skills/clickhouse-js-node-rowbinary/src/readers/compile.ts, dataTypeReader() did not have a handler for case "Tuple". As a result, folding an empty tuple AST fell through to the default branch and threw:

RowBinaryTypeError: unsupported RowBinary type: Tuple

Additionally, tupleReader() previously checked named via names.length === readers.length && names.every((n) => n.length > 0). For empty tuples where names and readers are both empty arrays ([]), [].every(...) evaluated to true, causing an empty tuple to be erroneously dispatched to readTupleNamed({}) (which returns an object {}) instead of readTuple([]) (which returns an array []).

Changes

1. compile.ts: Added case "Tuple": return tupleReader(node); to dataTypeReader().
2. compile.ts: Updated tupleReader() so named requires names.length > 0 before treating a tuple as a named object tuple.
3. compile.test.ts: Added unit tests validating that Tuple(), Tuple(Tuple()), and Tuple(Tuple(), UInt8) compile cleanly and decode the expected zero-byte tuples without error.

Verification

• npm run typecheck in skills/clickhouse-js-node-rowbinary passed with 0 errors.
• npx vitest run -t "empty Tuple" tests/compile.test.ts passed 3/3 tests cleanly.
• npx tsc -p tsconfig.build.json built without errors.

Partially addresses #1000.