perf(utils): reduce highway hash key setup (#5434)

* fix: keep hotpath gate csv paths clean

Redirect the enhanced bench driver's verbose output away from command substitution so run_hotpath_warp_ab.sh records only the candidate cell path before passing baseline_compare.csv files to the gate.

Co-Authored-By: heihutu <heihutu@gmail.com>

* perf(utils): reduce highway hash key setup

Cache the parsed HighwayHash keys as compile-time constants and add a criterion benchmark for the PUT hash hotpath.

Co-Authored-By: heihutu <heihutu@gmail.com>

---------

Co-authored-by: heihutu <heihutu@gmail.com>

crates/utils/Cargo.toml

@@ -58,11 +58,16 @@ url = { workspace = true, optional = true }
 zstd = { workspace = true, optional = true }
 
 [dev-dependencies]
+criterion = { workspace = true, features = ["html_reports"] }
 tempfile = { workspace = true }
 tokio = { workspace = true, features = ["macros", "rt"] }
 temp-env = { workspace = true }
 proptest = "1"
 
+[[bench]]
+name = "hash_hotpath_benchmark"
+harness = false
+
 [target.'cfg(windows)'.dependencies]
 windows = { workspace = true, optional = true, features = ["Win32_Storage_FileSystem"] }