[Router] Add bucket-aware policy domains and native cache indexing (#38108)

Signed-off-by: Vincent Gao <vincentbo@linux.alibaba.com>
Co-authored-by: inkcherry <mingzhi.liu@amd.com>
Co-authored-by: yangbodong22011 <13137470+yangbodong22011@users.noreply.github.com>

experimental/sgl-router/tests/proxy/common/cache_aware_fixture.rs

@@ -13,7 +13,7 @@ use sgl_router::config::{
 
 pub const MODEL: &str = "deepseek-v4-tiny";
 
-/// A single-model `cache_aware_zmq` router. Discovery is a placeholder because
+/// A single-model native `cache_aware` router. Discovery is a placeholder because
 /// every caller installs its own `WorkerRegistry`.
 pub fn config() -> Config {
     Config {
@@ -25,11 +25,13 @@ pub fn config() -> Config {
         model: ModelConfig {
             id: MODEL.into(),
             tokenizer_path: "tests/fixtures/tiny_tokenizer.json".into(),
-            policy: PolicyKind::CacheAwareZmq,
+            policy: PolicyKind::CacheAware,
+            decode_policy: Default::default(),
+            bucket_config: None,
             circuit_breaker: None,
             cache_aware: Some(CacheAwareConfig::default()),
-            sticky: None,
             affinity: None,
+            sticky: None,
             fused: None,
             eligibility: None,
         },