add frontend threadpool to database

Signed-off-by: Jason Volk <jason@zemos.net>

src/database/Cargo.toml

@@ -36,6 +36,7 @@ zstd_compression = [
 
 [dependencies]
 arrayvec.workspace = true
+async-channel.workspace = true
 conduit-core.workspace = true
 const-str.workspace = true
 futures.workspace = true