edge-bench-rs: file stems and subject remainders by hand, mimalloc

The suffix and remainder regexes were most of a new file's description
(333k on boneless 2026): now plain byte matching, with the regex versions
kept as the reference in a test of tricky names and subjects. mimalloc
for the many small strings. Boneless 2026: 360k -> 495k headers/s;
check.ts still finds the outputs identical on all three captures.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tools/edge-bench-rs/Cargo.lock

@@ -121,6 +121,7 @@ dependencies = [
  "chrono",
  "flate2",
  "md-5",
+ "mimalloc",
  "regex",
  "rustc-hash",
  "sha1",
@@ -238,6 +239,15 @@ version = "0.2.190"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ce5d3ddc6d3fa000eb1536d85e147bfe31aacaba692ed6a876f95cb7c855be78"
 
+[[package]]
+name = "libmimalloc-sys"
+version = "0.1.49"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6a45a52f43e1c16f667ccfe4dd8c85b7f7c204fd5e3bf46c5b0db9a5c3c0b8e9"
+dependencies = [
+ "cc",
+]
+
 [[package]]
 name = "log"
 version = "0.4.34"
@@ -260,6 +270,15 @@ version = "2.8.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cf8baf1c55e62ffcace7a9f06f4bd9cd3f0c4beb022d3b367256b91b87513d98"
 
+[[package]]
+name = "mimalloc"
+version = "0.1.52"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2d4139bb28d14ad1facf21d5eb8825051b326e172d216b39f6d31df53cc97862"
+dependencies = [
+ "libmimalloc-sys",
+]
+
 [[package]]
 name = "num-traits"
 version = "0.2.19"