feat(serve): add remote browser control over TCP with token auth

Exposes a local browser over a TCP socket so remote machines can
  control it using the same CLI and Python API. Token auth (auto-generated
  via secrets.token_urlsafe) is on by default; --no-auth disables it.
  Profile routing via _route message field lets clients target specific
  browser instances on the remote host. BROWSER_CLI_PROFILE is forwarded
  automatically so --browser flag works transparently over remote.
  - browser-cli serve [--host] [--port] [--token] [--no-auth]
  - browser-cli --remote HOST:PORT --token TOKEN <command>
  - BrowserCLI(remote="host:port", token="...").tabs_list()

browser_cli/cli.py

@@ -24,6 +24,7 @@ from browser_cli.commands.search import search_group
 from browser_cli.commands.page import page_group
 from browser_cli.commands.storage import storage_group
 from browser_cli.commands.cookies import cookies_group
+from browser_cli.commands.serve import cmd_serve
 from browser_cli.client import (
     send_command,
     BrowserNotConnected,
@@ -164,14 +165,26 @@ def _print_version(ctx, param, value):
     "--browser", default=None, metavar="ALIAS",
     help="Browser profile alias to target (required when multiple browsers are active).",
 )
+@click.option(
+    "--remote", default=None, metavar="HOST:PORT",
+    help="Connect to a remote browser exposed via 'browser-cli serve'.",
+)
+@click.option(
+    "--token", default=None, metavar="TOKEN",
+    help="Auth token for the remote browser-cli serve instance.",
+)
 @click.pass_context
-def main(ctx, browser):
+def main(ctx, browser, remote, token):
     """Control your running browser from the terminal via a Chrome extension."""
     ctx.ensure_object(dict)
     ctx.obj["browser"] = browser
     ctx.obj["browser_explicit"] = browser is not None
     if browser:
         os.environ["BROWSER_CLI_PROFILE"] = browser
+    if remote:
+        os.environ["BROWSER_CLI_REMOTE"] = remote
+    if token:
+        os.environ["BROWSER_CLI_TOKEN"] = token
 
 
 # ── Sub-command groups ─────────────────────────────────────────────────────────
@@ -186,6 +199,7 @@ main.add_command(search_group)
 main.add_command(page_group)
 main.add_command(storage_group)
 main.add_command(cookies_group)
+main.add_command(cmd_serve)
 
 
 # ── clients ────────────────────────────────────────────────────────────────────