feat: implement Clash-like Fake IP feature for DNS optimization

[darkSuperman]

Description

This PR introduces a Fake IP feature (similar to the implementation in Clash) to optimize DNS resolution and connection latency, as well as to prevent local DNS leaks.

How it works & Motivation

Normally, a client resolves a domain name first and then initiates a connection to the returned IP, costing an extra DNS RTT.
With this Fake IP implementation:

1. DNS Interception: A local DNS server is spun up (using hickory-dns). When the client queries a domain, it immediately returns an unused pseudo-IP (e.g., 198.18.0.x from a configured pool) and records the mapping in an LRU cache.
2. Zero Round-Trip: The client saves the real DNS resolution time and connects mapped Fake IP directly.
3. Domain Restoration: During the proxy connection phase (in src/address.rs), the proxy detects the Fake IP, retrieves the original FQDN mapped in the cache, and routes the proxy request using the actual domain name.

Implementation Details

• FakeIpManager: A thread-safe LRU cache (exposed globally via std::sync::OnceLock) to store #Domain -> Fake IP and #Fake IP -> Domain mappings.
• DNS Server: Integrated a lightweight UDP DNS server to parse DNS queries and return Fake IP binary records.
• Connection Interception: Injected restore_fake_ip() globally into the address parsing phase so any outbound connection utilizing a Fake IP seamlessly recovers its target FQDN before leaving shoes.