Add self-authenticating .rings names

[RyanKung]

Summary

• add .rings self-authenticating service name records backed by Chord storage
• expose publish/resolve APIs through processor, JSON-RPC, native CLI, and browser provider
• reject human-readable aliases in v1 and validate owner-bound signatures, network id, expiry, and sequence selection

Closes #662.

Validation

• cargo check -p rings-node --no-default-features --features node
• cargo check -p rings-node --target wasm32-unknown-unknown --no-default-features --features browser
• cargo test -p rings-node --no-default-features --features node rings_name
• cargo +nightly fmt --all -- --check
• git diff --check