feat(kv-events): expose structured KV-event publisher block on /server_info (#25844)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

python/sglang/srt/entrypoints/http_server.py

@@ -636,12 +636,18 @@ async def server_info():
         await _global_state.tokenizer_manager.get_internal_state()
     )
 
+    server_args = _global_state.tokenizer_manager.server_args
+
     # server_args.model_config is not serializable but should be excluded by asdict.
     return {
-        **dataclasses.asdict(_global_state.tokenizer_manager.server_args),
+        **dataclasses.asdict(server_args),
         **_global_state.scheduler_info,
         "internal_states": internal_states,
         "version": __version__,
+        # Structured KV-event publisher descriptor for KV-aware routers.
+        # `None` when publishing is disabled or misconfigured; see
+        # `ServerArgs.describe_kv_events_publisher` for the precise contract.
+        "kv_events": server_args.describe_kv_events_publisher(),
     }