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

crates/lanspread-compat/Cargo.toml

@@ -12,6 +12,7 @@ lanspread-db = { path = "../lanspread-db" }
 
 blake3 = { workspace = true }
 eyre = { workspace = true }
+rayon = { workspace = true }
 serde = { workspace = true }
 sqlx = { workspace = true }
 tokio = { workspace = true }