perf: lock-free routing

[leiysky]

Membership and HashRing are read-heavy data structures. Use lock-free multi version to reduce lock usage and full clone.

[Copilot]

Pull Request Overview

This PR refactors the gossip system to use lock-free data structures for improved performance in read-heavy scenarios. It replaces RwLock synchronization with ArcSwap for the membership and hash ring data structures to reduce lock contention and eliminate unnecessary cloning.

• Replace RwLock<Membership> and RwLock<Arc<HashRing<Uuid>>> with ArcSwap variants
• Add utility methods to Membership for better integration with the new lock-free approach
• Update all membership and ring access patterns to use atomic operations instead of read/write locks

Reviewed Changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated 2 comments.

File	Description
crates/gossip/src/member.rs	Adds into_members() method and FromIterator implementation for Membership
crates/gossip/src/gossip.rs	Replaces RwLock with ArcSwap for membership and ring, updates all access patterns
crates/gossip/Cargo.toml	Adds arc-swap dependency

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[tisonkun]

Would this technique applicible for client's route table state also?