wip: fix: extensions loading

[nathanfallet]

Fixes #50

This is a work in progress since it requires more changes to work.

 The Extensions.loadUnpacked CDP method requires --remote-debugging-pipe mode, which uses stdin/stdout for CDP communication instead of WebSockets over --remote-debugging-port. This is a much bigger architectural change than initially expected. It would require: 1. New connection type: Create a pipe-based connection that communicates via stdin/stdout instead of WebSocket 2. Process management changes: Handle reading from and writing to the browser process's stdout/stdin 3. Message framing: Implement the CDP message protocol over pipes (newline-delimited JSON) 4. Potentially conditional logic: Maybe support both modes - WebSocket for most use cases, pipe for extensions Looking at the error "Method not available. (code: -32000)", this confirms Chrome is refusing the Extensions.loadUnpacked command because we're not using pipe mode. Options: 1. Implement full pipe mode support - This is the correct long-term solution but requires significant refactoring of the connection layer 2. Document the limitation - Note that extensions require pipe mode which isn't currently supported, and this is a known limitation