Add protocolTimeout support to puppeteer launch options

[zenom]

Problem

Batch print jobs with large case counts can exceed Puppeteer's default 180 second CDP protocol timeout, resulting in:

ProtocolError: Network.enable timed out. Increase the 'protocolTimeout' setting in launch/connect calls for a higher timeout if needed.

This was reported in #248.

Root cause

Puppeteer exposes protocolTimeout in its launch options to raise this limit, but Grover never extracted it into launchParams — the value would silently pass through to page.pdf() where Puppeteer ignores it entirely.

Fix

Extract protocolTimeout from the options hash and pass it into launchParams before calling puppeteer.launch(), consistent with how launchTimeout, executablePath, and other launch options are handled.

Also adds protocol_timeout to the integer coercion list in OptionsFixer so it behaves consistently when set via HTML meta tags, which always produce string values.

Usage

Grover.new(html, protocol_timeout: 300_000).to_pdf

Or globally:

Grover.configure do |config|
  config.options = { protocol_timeout: 300_000 }
end