deps: add tiktoken-rs

Author: DaleSeo

Cargo.lock

@@ -26,6 +26,7 @@ rmcp = { version = "0.2", features = [
 serde.workspace = true
 serde_json.workspace = true
 thiserror.workspace = true
+tiktoken-rs = "0.7.0"
 tokio.workspace = true
 tracing.workspace = true
 tracing-subscriber = { version = "0.3.19", features = ["env-filter"] }