Add listResourceTemplates support for resource discovery

[Copilot]

AI agents currently discover resources (console logs, screenshots) only after creation. This adds listResourceTemplates to advertise available resource patterns upfront.

Changes

• Add ListResourceTemplatesRequestSchema handler in requestHandler.ts

  • Exposes console://logs template for browser console logs
  • Exposes screenshot://{name} template for named screenshots with URI template variable

• Update server capabilities in index.ts

  • Declare resources.listChanged: true to indicate dynamic resource support

Resource Templates Exposed

{
  resourceTemplates: [
    {
      uriTemplate: "console://logs",
      name: "Browser console logs",
      mimeType: "text/plain",
      description: "Access browser console output captured during page interactions"
    },
    {
      uriTemplate: "screenshot://{name}",
      name: "Page screenshots", 
      mimeType: "image/png",
      description: "Access screenshots by name taken via playwright_screenshot tool"
    }
  ]
}

Agents can now understand resource URI patterns before resources exist, enabling better planning and discovery flows.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>support listResourceTemplates</issue_title>
<issue_description>Support listResourceTemplates to enable agent to better discover snapshots.

</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes support listResourceTemplates #149

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