feat: Update project structure and configuration files

backend/buf.gen.yaml

@@ -0,0 +1,23 @@
+version: v2
+inputs:
+  - directory: proto
+managed:
+  enabled: true
+  override:
+    - file_option: go_package_prefix
+      value: quyun/pkg/proto
+
+plugins:
+  - local: protoc-gen-go
+    out: pkg/proto
+    opt: paths=source_relative
+  # - local: protoc-gen-grpc-gateway
+  #   out: pkg/proto
+  #   opt:
+  #     - paths=source_relative
+  #     - generate_unbound_methods=true
+  - local: protoc-gen-go-grpc
+    out: pkg/proto
+    opt: paths=source_relative
+  # - local: protoc-gen-openapiv2
+  #   out: docs/proto