fix: pass timeout to SOCKS5 handshake reads to prevent infinite blocking

[muhamedfazalps]

_init_socks5_connection calls stream.read() three times without passing a timeout argument. SyncStream.read() calls settimeout(None) which puts the socket into infinite blocking mode, overriding any timeout set during socket creation. This causes requests to hang indefinitely when using a SOCKS5 proxy that stalls during the handshake.

Fixes #1089

import httpx

# Before: hangs forever if SOCKS5 proxy stalls during handshake
# After: timeout is respected, raises ReadTimeout
proxy = httpx.Proxy("socks5://127.0.0.1:9150")
with httpx.Client(proxy=proxy, timeout=5.0) as client:
    client.get("http://example.com")  # now times out correctly