docs: update documents

docs/phase_chart_zh.md

@@ -0,0 +1,33 @@
+---
+description: Pingap 处理流程
+---
+
+```mermaid
+ graph TD;
+    start("new request")-->request_filter;
+    request_filter-->upstream_peer;
+
+    upstream_peer-->Connect{{IO: connect to upstream}};
+
+    Connect--connection success-->connected_to_upstream;
+    Connect--connection failure-->fail_to_connect;
+
+    connected_to_upstream-->upstream_request_filter;
+    upstream_request_filter --> SendReq{{IO: send request to upstream}};
+    SendReq-->RecvResp{{IO: read response from upstream}};
+    RecvResp-->upstream_response_filter-->response_filter-->upstream_response_body_filter-->response_body_filter-->logging-->endreq("request done");
+
+    fail_to_connect --can retry-->upstream_peer;
+    fail_to_connect --can't retry-->fail_to_proxy--send error response-->logging;
+
+    RecvResp--failure-->IOFailure;
+    SendReq--failure-->IOFailure;
+    error_while_proxy--can retry-->upstream_peer;
+    error_while_proxy--can't retry-->fail_to_proxy;
+
+    request_filter --send response-->logging
+
+
+    Error>any response filter error]-->error_while_proxy
+    IOFailure>IO error]-->error_while_proxy
+```