perf(catalog): parallelize production manifest hashing

Production catalog generation previously prepared every game serially and computed transfer-chunk hashes for extracted .eti files even though those hashes were discarded. Enable Rayon-backed BLAKE3 hashing, process selected games through the shared available-CPU pool, and hash large read blocks with update_rayon. Extracted outputs now use a whole-file-only hash path. Manifest collection remains deterministic and the independent second verification pass is preserved.

Test Plan:
- `just clippy` -- passed
- `just test` -- passed

Cargo.lock

@@ -247,6 +247,7 @@ dependencies = [
  "cfg-if",
  "constant_time_eq",
  "cpufeatures 0.3.0",
+ "rayon-core",
 ]
 
 [[package]]
@@ -614,6 +615,25 @@ dependencies = [
  "crossbeam-utils",
 ]
 
+[[package]]
+name = "crossbeam-deque"
+version = "0.8.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5181e0de7b61eb03a81e347d6dd8797bae9da5146707b51077e2d71a54ec0ceb"
+dependencies = [
+ "crossbeam-epoch",
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-epoch"
+version = "0.9.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2d6914041f254d6e9176c01941b21115dcfb7089e55135a35411081bd106ef3f"
+dependencies = [
+ "crossbeam-utils",
+]
+
 [[package]]
 name = "crossbeam-queue"
 version = "0.3.13"
@@ -2056,6 +2076,7 @@ dependencies = [
  "blake3",
  "eyre",
  "lanspread-db",
+ "rayon",
  "serde",
  "sqlx",
  "tokio",
@@ -3067,6 +3088,26 @@ version = "0.6.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "20675572f6f24e9e76ef639bc5552774ed45f1c30e2951e1e99c59888861c539"
 
+[[package]]
+name = "rayon"
+version = "1.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fb39b166781f92d482534ef4b4b1b2568f42613b53e5b6c160e24cfbfa30926d"
+dependencies = [
+ "either",
+ "rayon-core",
+]
+
+[[package]]
+name = "rayon-core"
+version = "1.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "22e18b0f0062d30d4230b2e85ff77fdfe4326feb054b9783a3460d8435c8ab91"
+dependencies = [
+ "crossbeam-deque",
+ "crossbeam-utils",
+]
+
 [[package]]
 name = "rcgen"
 version = "0.14.8"