feat(trie): expose payload state root receiver (#26431)

[bitwiseguy]

Cherry-picked merge commit 92cf59e2bee8329dbe654088255a889f46469bf4 from this upstream reth pr: https://github.com/paradigmxyz/reth/pull/26431

[bitwiseguy]

The lint failures are unrelated to the one-file change in this PR and come from rerunning the historical f2eecc6 tree with moving CI inputs.

• fmt, clippy, clippy binaries / ethereum, and book use floating Rust toolchains. The current toolchains now report formatting and semicolon_in_expressions_from_non_local_macros errors in pre-existing files outside this PR, including crates/rpc/ipc/src/server/mod.rs, crates/engine/local/src/miner.rs, and crates/storage/db-common/src/implementation/mdbx/mod.rs.
• cargo deny uses the current RustSec database and now rejects the pre-existing ruint 1.18.0 lock entry under RUSTSEC-2026-0220, which was issued on July 30. The original upstream CI ran on July 20.

The original upstream lint workflow passed fmt, workspace clippy, binary clippy, book, and cargo deny. Its nightly was nightly-2026-07-20 / rustc 1.99.0-nightly (9f36de775 2026-07-19).

As an independent check on this PR commit, I reran the historical toolchain locally:

cargo +nightly-2026-07-20 fmt --all --check
RUSTFLAGS="-D warnings" cargo +nightly-2026-07-20 clippy -p reth-trie-parallel --all-targets --all-features --locked

Both passed. The PR changes only crates/trie/parallel/src/state_root_task.rs; none of the current lint diagnostics point to that file.

[sebastianst]

Approving since the failing CI checks are expected for a cherry pick on an old revision, as @bitwiseguy has explained. Changes look good otherwise.