Preserve coordination inbox state on tool interruptions

[CoreyShupe]

Summary

• Add public InterruptSessionWork command, gRPC operation and SDK method for coordinator tools.
• Reuse current-session cancellation without changing inbox pause state; manual CancelSessionWork keeps pausing.
• Cover pending FIFO dispatch, cancellation/idle boundaries, retry deduplication, manual/pre-paused states and same-runtime session isolation.

Validation

• cargo test --all-targets --all-features passed
• focused followups: 19 passed after final fixture/isolation additions
• cargo fmt --all -- --check passed
• cargo clippy --all-targets --all-features -- -D warnings passed
• cargo clippy --locked -p nakode-runtime -- -D warnings passed
• independent code review: no actionable defects

No live sessions, storage or services were modified.