RUST-BUG-110: bind peer service to HELLO admission

[itlezy]

Summary

• disconnect actively banned identities during HELLO binding
• gate inbound and outbound peer service on an explicit direction-aware HELLO state machine
• hold promoted upload grants until the expected identity is bound
• preserve legacy EMULEINFO preludes, simultaneous HELLO, and plain or packed PORTTEST compatibility
• separate expected route identity from bound session identity and bound pre-establishment work

Validation

• cargo test -p emulebb-ed2k -- --test-threads=1 (1024 passed)
• cargo test -p emulebb-ed2k ed2k_tcp::tests -- --test-threads=1 (159 passed)
• cargo fmt --all -- --check
• cargo clippy -p emulebb-ed2k --lib -- -D warnings -A unfulfilled-lint-expectations

The Clippy allowance isolates seven pre-existing stale lint expectations in unrelated server and NAT files.