fix: release peer lock before persistence

[ovitrif]

Fixes #99

Related to synonymdev/bitkit-android#986.
Addresses the Node.listPeers ANR tracked in synonymdev/bitkit-android#1036.

Summary

• Backport Fully switch to async KVStore persistence lightningdevkit/ldk-node#919's async KVStore peer-persistence design.
• Serialize peer mutations with a Tokio mutex, encode each snapshot under the peer RwLock, and release that lock before awaiting persistence.
• Preserve fork address updates, RGS recovery exclusion ordering, and retryable add, address-update, and removal failures.
• Bridge synchronous node APIs at the runtime boundary while async event and recovery paths await persistence directly.
• Prepare Rust and mobile binding artifacts as 0.7.0-rc.61.

Validation

• Local verification: cargo fmt --check, git diff --check, and cargo test --features uniffi --lib (93 passed).
• Binding verification: ./bindgen.sh completed for JVM Kotlin, Python, Swift, and Android; JVM Gradle, Swift framework assembly, Android three-ABI build-ID, 16 KiB alignment, debug-symbol, stripped-library, and AAR checks passed.
• Swift archive verification: SHA-256 8662cdf7f52725ceab0ebf68b7ded139dfbbb0b4b5ec4e451cb5f7cce505ce68 matches Package.swift and the uploaded release asset.

QA Notes

• This PR is stacked on fix: prevent electrum runtime self-drop #100 at 080b5f20ef3a2e6a1b706a84b087bd354bb71ecb.
• Synchronous peer reads remain available while async persistence is pending. Failed persistence restores the previous in-memory state so the mutation can be retried.

Release

• v0.7.0-rc.61