Improve structured logging and observability

Establish and enforce structured logging with tracing spans and performance optimization

High-concurrency Rust when structured field logging and span-based context tracing beat free-text logs

• · Rust codebase (Anchor SSV client)
• · Existing tracing infrastructure
• · High-load async task patterns

• · Structured field definitions
• · Span instrumentation patterns
• · Error context capture patterns
• · Performance audit findings with fixes

• · tracing
• · tracing-subscriber
• · tracing-appender

Rust/Tokio async runtime; tracing crate integrated; developer familiarity with structured logging

Performance regression from logging hot paths; span context lost in async handoffs; log level checks missing

• · Universal Code Quality Principles referenced
• · Span instrumentation pattern documented
• · Performance checks required (enabled!(Level::DEBUG))
• · Error context via span hierarchy