feat: запасной MTProto TCP и CF-прокси через свой домен (по образцу Flowseal/tg-ws-proxy); 2.0.0-beta.17 (#73)

* feat: native MTProto TCP fallback and CF-proxy domains, after Flowseal/tg-ws-proxy; 2.0.0-beta.17

Two routes Flowseal/tg-ws-proxy has and TGLock lacked.

Native TCP fallback. When every WebSocket route for a DC fails, TGLock now
tries plain obfuscated2 MTProto to the DC's primary address, which the
CDN203 route already used. Measured from a Russian ISP: TLS to .51, .91,
.50, .100 and .5 was cut, while native TCP to each answered req_pq_multi,
for main and media DCs alike. 149.154.167.220 is a WebSocket frontend only
and gets no TCP route. TCP opens before Telegram answers, so it is raced
only after all other routes failed; it can never displace a slower working
WebSocket. Raw TCP stays restricted to the pinned Telegram addresses.

CF proxy. A user's own Cloudflare domain with kws1..kws5/kws203 records
pointing at Telegram proxies the WebSocket without a Worker or its limits
(--cf-proxy, cf_proxy in tglock.toml, a GUI field; docs/CF_PROXY.md).

GUI settings now deserialize with serde(default): a file written before a
field existed used to fail to parse and silently reset to defaults.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* style: cargo fmt

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: babin <Thartewerner536e@engineer.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "tglock"
-version = "2.0.0-beta.16"
+version = "2.0.0-beta.17"
 edition = "2021"
 rust-version = "1.88"
 description = "Telegram unblock via local WebSocket tunnel"