feat: new router and benchmark setup

src/router/estimated_ttft.rs

@@ -58,8 +58,11 @@ impl Router for EstimatedTtftRouter {
             let miss_tokens = residency.miss_blocks.saturating_mul(inst.block_size_tokens);
             let kv_prepare = self.ttft_model.kv_prepare_time_s(residency);
             let first_token_tail = self.ttft_model.first_token_tail_s();
-            let cost =
-                drain + scheduler + kv_prepare + inst.compute.prefill_time(miss_tokens) + first_token_tail;
+            let cost = drain
+                + scheduler
+                + kv_prepare
+                + inst.compute.prefill_time(miss_tokens)
+                + first_token_tail;
 
             candidates.push(CandidateInfo {
                 instance: inst.id,
@@ -72,7 +75,8 @@ impl Router for EstimatedTtftRouter {
 
             // Minimise (cost, queue_len, -local_prefix).
             let ql = inst.queue_len();
-            let reusable = residency.l0_hit_blocks + residency.l1_hit_blocks + residency.remote_hit_blocks;
+            let reusable =
+                residency.l0_hit_blocks + residency.l1_hit_blocks + residency.remote_hit_blocks;
             let better = cost < best_cost
                 || (cost == best_cost && ql < best_queue)
                 || (cost == best_cost && ql == best_queue && reusable > best_reuse);