feat: support decimal

[RaphDal]

This PR adds decimal support.

This is a tandem pr for:

• feat(core): support for Decimal questdb#6068

Usage

Textual representation

import { Sender } from "@questdb/nodejs-client";

async function runDecimals() {
  const sender = await Sender.fromConfig(
    "tcp::addr=127.0.0.1:9009;protocol_version=3",
  );

  await sender
    .table("fx")
    // textual ILP form keeps the literal and its exact scale
    .decimalColumnText("mid", "1.234500")
    .atNow();

  await sender.flush();
  await sender.close();
}

runDecimals().catch(console.error);
// Resulting ILP line: fx mid=1.234500d

Binary representation

It is recommended to use the binary representation for better ingestion performance and reduced payload size (for bigger decimals).

import { Sender } from "@questdb/nodejs-client";

async function runDecimals() {
  const sender = await Sender.fromConfig(
    "tcp::addr=127.0.0.1:9009;protocol_version=3",
  );

  await sender
    .table("fx")
    // textual ILP form keeps the literal and its exact scale
    .decimalColumnUnscaled("mid", 123456n, 3) // 123456 * 10^-3 = 123.456
    .atNow();

  await sender.flush();
  await sender.close();
}

runDecimals().catch(console.error);

Progress

• support binary and text formats
• release decimal on QuestDB OSS

[RaphDal]

@CodeRabbit review