style(context): bersihkan warning clippy pedantic di squash.rs dan dedup.rs

Perbaikan gaya murni (format! di-append ke String -> write!, syntax
perbandingan yang lebih jelas, backtick di doc comment) tanpa
mengubah perilaku -- semua test tetap hijau.

src/app/runtime/context/dedup.rs

@@ -82,7 +82,7 @@ pub fn collapse(messages: &[ChatMessage]) -> (Vec<ChatMessage>, bool) {
 ///
 /// Why hash the arguments: keeps the key a fixed, short size regardless
 /// of argument payload size. `serde_json::to_string` is already
-/// canonical here — this codebase doesn't enable serde_json's
+/// canonical here — this codebase doesn't enable `serde_json`'s
 /// `preserve_order` feature, so `Value::Object` is backed by a
 /// `BTreeMap` and always serializes keys in sorted order.
 fn dedup_key(tool_name: &str, canonical_args: &str) -> String {