feat: rewrite cloakserve as CDP multiplexer with per-connection fingerprint seeds

Spawns a separate Chrome process per unique fingerprint seed, all behind
a single port (9222). Clients specify seeds and fingerprint params via
query string on the CDP URL:

  connect_over_cdp("http://host:9222?fingerprint=12345&timezone=Asia/Tokyo")

Supports all --fingerprint-* flags as query params, geoip=true for
auto timezone/locale from proxy IP, and proxy= for per-process proxies.

- Rewrite bin/cloakserve from 57-line wrapper to aiohttp CDP multiplexer
- Add ChromePool with per-seed process management and port allocation
- Bidirectional WebSocket proxy for CDP traffic
- URL rewriting for /json/version, /json/list, and WS paths
- Rename _build_args -> build_args, _maybe_resolve_geoip -> maybe_resolve_geoip
- Add aiohttp + websockets to serve optional deps
- Dockerfile installs .[serve] extras
- Add 20 unit tests for cloakserve (param parsing, CLI args, URL rewriting)

pyproject.toml

@@ -56,6 +56,7 @@ dependencies = [
 [project.optional-dependencies]
 geoip = ["geoip2>=4.0"]
 patchright = ["patchright>=1.40"]
+serve = ["aiohttp>=3.9", "websockets>=12.0"]
 dev = ["pytest>=7.0", "pytest-asyncio>=0.23"]
 
 [project.scripts]