feat: initial memo store

proto/store/memo.proto

@@ -0,0 +1,29 @@
+syntax = "proto3";
+
+package slash.store;
+
+import "store/common.proto";
+
+option go_package = "gen/store";
+
+message Memo {
+  int32 id = 1;
+
+  int32 creator_id = 2;
+
+  int64 created_ts = 3;
+
+  int64 updated_ts = 4;
+
+  RowStatus row_status = 5;
+
+  string name = 6;
+
+  string title = 7;
+
+  string content = 8;
+
+  repeated string tags = 9;
+
+  Visibility visibility = 10;
+}