luci-app-ssr-plus: fix authenticated SOCKS5 startup

[Opnwall]

Summary

• resolve SOCKS5 server hostnames before passing them to ipt2socks
• pass username and password as distinct command arguments
• fail with a clear log message when hostname resolution fails
• apply the fix to both TCP redirect and UDP TPROXY startup paths

Root cause

The authentication options were assembled into one string and then expanded as a single quoted argument. As a result, ipt2socks received -a user -k password as one argv entry instead of four entries and failed to start. In addition, the configured server value was passed directly to ipt2socks -s; a hostname therefore failed because this backend expects a resolved IPv4 address.

Validation

• sh -n luci-app-ssr-plus/root/etc/init.d/shadowsocksr
• git diff --check
• validated on OpenWrt with luci-app-ssr-plus 196-r7 using an authenticated SOCKS5 hostname
• confirmed eight TCP and eight UDP ipt2socks workers, DNS2TCP operation, and proxied Google/GitHub access