545e74d0ea correctly stopped writing telegram.proxy_url into TELEGRAM_PROXY
for a multiplexed secondary, but _build_ptb_requests still resolved the proxy
only from that env var, so the secondary silently connected direct (or via the
default's proxy). #100448 had deliberately left this bridge unscoped for that
reason; this finishes the consumer migration instead.
_apply_yaml_config seeds proxy_url into extra and resolve_proxy_url gains a
`configured` rung: scoped TELEGRAM_PROXY → the profile's YAML → HTTPS_PROXY/
HTTP_PROXY/ALL_PROXY (trust_env) → macOS system proxy, with NO_PROXY semantics
unchanged.
Refs #108440 (finding 6)
teknium1
7c9175f48c