Replace parking_lot Mutex with tokio Mutex to align with kona-node async primitives

[teddyknox]

Motivation

• parking_lot::Mutex is incompatible with certain concurrency primitives used by kona-node.
• We need an async-aware mutex that cooperates with the Tokio scheduler and avoids blocking the runtime.

Change summary

• Replace parking_lot::Mutex on async code paths with tokio::sync::Mutex.
• Update all call sites to lock().await and adjust signatures to be async where necessary.
• Keep tests and pure-sync helpers on std::sync::Mutex.

Scope

• Updated modules: server, health, probe, debug_api (runtime paths) now use tokio::sync::Mutex.
• Test and harness code (e.g., request trackers, port allocators) use std::sync::Mutex.
• Minor refactors around call-sites to make locking async-safe and avoid .await inside non-async contexts.

Incidental behavior adjustments (in service of the migration)

• Execution-mode handling and health checks were tightened to ensure locks are taken asynchronously and health state updates are non-blocking.
• Builder calls (e.g., FCU/newPayload) are gated consistently behind execution mode and health, ensuring we don’t hold sync locks across awaits.

Testing and verification

• Updated unit/integration tests to use std::sync::Mutex for mock state.
• Assertions and harnesses adjusted to reflect non-blocking health updates and builder gating.
• No external API shape changes; endpoints retain existing request/response formats.

Risk and rollout

• Touches synchronization across core request paths; requires careful soak in staging.
• Look for deadlock regressions, starvation, or unexpected latency under load.

Follow-ups

• Audit remaining modules (e.g., flashblocks/inbound.rs) for any lingering parking_lot::Mutex on async paths and migrate to tokio::sync::Mutex where applicable.

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1 Skipped Deployment

Project	Deployment	Preview	Comments	Updated (UTC)
rollup-boost	Ignored			Nov 6, 2025 8:16pm

[theochap]

nit: We should tokio mutexes here.

Suggested change

	use std::sync::Mutex;
	use tokio::sync::Mutex;

[theochap]

We should use tokio mutexes here

Suggested change

	use std::sync::Mutex;
	use tokio::sync::Mutex;

[0xForerunner]

parking_lot::Mutex is incompatible with certain concurrency primitives used by kona-node.

I'm not convinced that this is necessary. From tokios own documentation:

Contrary to popular belief, it is ok and often preferred to use the ordinary Mutex from the standard library in asynchronous code.

Maybe you could provide some more detailed information on why you think this is required.