Verify WebMCP tools

Runtime check that a site's WebMCP tools register and work as designed. Runs standalone on any site with existing tools, and serves as step 5 of this plugin's webmcp skill.

Treat tools like a public API: a tool is done when an agent can call it, not when the build passes.

Prerequisites

• The site runs locally (its own dev script or runbook; never assume a harness exists).
• Chrome installed. No flags or Canary needed for the packaged driver; it launches Chrome itself with --enable-features=WebMCPTesting,DevToolsWebMCPSupport.

Drivers, in order of preference