[feature] CDP attach mode — connect to existing Chrome session without extension

[FelixIsaac]

Summary

Add an alternative server.js mode that connects to a running Chrome via Chrome DevTools Protocol (CDP) instead of requiring the native messaging extension.

Motivation

• Users are already logged into Chrome — no re-auth needed
• Lower friction: no extension install, just launch Chrome with a flag
• Useful on managed devices where extensions can't be installed

How it works

Launch Chrome with:

chrome.exe --remote-debugging-port=9222 --user-data-dir="%USERPROFILE%\ChromeProfile"

Then server.js connects via CDP (raw chrome-remote-interface or Playwright's connectOverCDP).

Implementation

• Add --mode cdp flag to server.js
• Auto-discover endpoint via http://localhost:9222/json/version
• Implement same tool surface (navigate, snapshot, click, etc.) via CDP calls
• Keep extension mode as default; CDP is opt-in

Notes

• Chrome M144+: must use --remote-debugging-port startup flag (not chrome://inspect)
• Same accessibility tree snapshot approach — no token cost regression

[FelixIsaac]

Status: Deferred — Nice-to-have

CDP attach mode (--remote-debugging-port) is blocked by Chrome 136+ on the default profile. The README already explains why Native Messaging was chosen. This feature would only work for non-default profiles. Low priority given the primary use case.