fix(telegram): honor proxy env vars in fallback transport (salvage #3411) (#3591)

* fix: keep gateway running through telegram proxy failures

- continue gateway startup in degraded mode when Telegram cannot connect yet
- ensure Telegram fallback transport also honors proxy env vars
- support reconnect retries without taking down the whole gateway

* test(telegram): cover proxy env handling in fallback transport

---------

Co-authored-by: kufufu9 <pi@local>

gateway/platforms/telegram_network.py

@@ -12,6 +12,7 @@ from __future__ import annotations
 import asyncio
 import ipaddress
 import logging
+import os
 import socket
 from typing import Iterable, Optional
 
@@ -43,6 +44,14 @@ _DOH_PROVIDERS: list[dict] = [
 _SEED_FALLBACK_IPS: list[str] = ["149.154.167.220"]
 
 
+def _resolve_proxy_url() -> str | None:
+    for key in ("HTTPS_PROXY", "HTTP_PROXY", "ALL_PROXY", "https_proxy", "http_proxy", "all_proxy"):
+        value = (os.environ.get(key) or "").strip()
+        if value:
+            return value
+    return None
+
+
 class TelegramFallbackTransport(httpx.AsyncBaseTransport):
     """Retry Telegram Bot API requests via fallback IPs while preserving TLS/SNI.
 
@@ -54,6 +63,9 @@ class TelegramFallbackTransport(httpx.AsyncBaseTransport):
 
     def __init__(self, fallback_ips: Iterable[str], **transport_kwargs):
         self._fallback_ips = [ip for ip in dict.fromkeys(_normalize_fallback_ips(fallback_ips))]
+        proxy_url = _resolve_proxy_url()
+        if proxy_url and "proxy" not in transport_kwargs:
+            transport_kwargs["proxy"] = proxy_url
         self._primary = httpx.AsyncHTTPTransport(**transport_kwargs)
         self._fallbacks = {
             ip: httpx.AsyncHTTPTransport(**transport_kwargs) for ip in self._fallback_ips