v0.5.19: chore: 0.5.19 (#237)

• run_task takes cloud_extensions, up to three distinct extension IDs from your Browser Use Cloud account,
  and loads them into the cloud browser it starts. Asking for extensions with local Chrome or an attached
  browser is an error, since neither can load them. Runs that ask for none are unchanged.

• fastbrowse can now be used from JavaScript with no Python on the machine. npm install fastbrowse installs a
  TypeScript SDK and, as an optional dependency, the agent as a native binary for macOS, Linux (glibc) or Windows.
  No install script runs and nothing is downloaded on first use. Fastbrowse.start() starts the binary and
  run(task, options) returns the RunResult a Python caller gets, with the same statuses, citations and cost
  lines. The secret resolver, until, onEvent and onFrame are functions in your own program, so a secret
  value stays there until the moment it is typed, and an AbortSignal cancels a run and closes its browser.
  output takes a Zod, ArkType or other Standard Schema that can write itself as JSON Schema, or a JSON Schema
  object; with the first, result.output is the data as that schema validated it, and has its type. A run fills
  flat string, number, integer and boolean fields today, and a schema with any other field ends unverified.
  The README has the install and a first run.

• fastbrowse serve --stdio is the entry point the SDK drives, and any program can speak to it: JSON-RPC 2.0,
  one message per line, with the methods initialize, run, run/cancel and shutdown. It runs one task at a
  time and takes its keys from the environment, as the command line does. run_task, the command line's
  existing flags and the MCP server are unchanged.

• One tag now publishes one version to PyPI and to npm. The release builds all five binaries and runs each through a
  handshake and a task on local Chrome before anything is published. npm publishing uses trusted publishing, as PyPI
  does, so no token is stored. CI fails when the npm version differs from the Python one. The macOS binaries carry
  an ad-hoc signature and are not notarized, the Windows binary is not signed, and there is no binary for Alpine or
  another musl system.