[Bug]: MCP: 0.0.0.0 is incorrectly translated to loopback for http mode, breaking non-loopback use #42952

Version

v1.63.0

Steps to reproduce

run the MCP server with --host 0.0.0.0, i.e.:

node /app/cli.js --headless --browser chromium --no-sandbox --port 8931 --host 0.0.0.0

This is the actual docker configuration recommended by the playwright-mcp documentation, and it doesn't work (the service binds to 127.0.0.1):

docker run -d -i --rm --init --pull=always \
  --entrypoint node \
  --name playwright \
  -p 8931:8931 \
  mcr.microsoft.com/playwright/mcp \
  /app/cli.js --headless --browser chromium --no-sandbox --port 8931 --host 0.0.0.0

Expected behavior

http binds to 0.0.0.0 when so configured

Actual behavior

http binds to 127.0.0.1 instead

Additional context

Line 56 of packages/playwright-core/src/tools/utils/mcp/http.ts replaces 0.0.0.0 with localhost when the normalizeloopback option is set (and this is only called in one place and is always set). 0.0.0.0 is not a loopback address, and doing this translation prevents non-localhost use without the explicit specification of an interface IP (and entirely so in a container environment where no such IP is available)

Environment

irrelevant