add $save command

src/ChatCommands.cc

@@ -1026,6 +1026,29 @@ static void server_command_convert_char_to_bb(shared_ptr<Client> c, const std::s
   send_get_player_info(c);
 }
 
+static void server_command_save(shared_ptr<Client> c, const std::string&) {
+  check_version(c, GameVersion::BB);
+  try {
+    c->game_data.save_character_file();
+    send_text_message(c, "Character data saved");
+  } catch (const exception& e) {
+    send_text_message_printf(c, "Can\'t save character:\n%s", e.what());
+  }
+  try {
+    c->game_data.save_system_file();
+    send_text_message(c, "System data saved");
+  } catch (const exception& e) {
+    send_text_message_printf(c, "Can\'t save system data:\n%s", e.what());
+  }
+  try {
+    c->game_data.save_guild_card_file();
+    send_text_message(c, "Guild Card data saved");
+  } catch (const exception& e) {
+    send_text_message_printf(c, "Can\'t save Guild Cards:\n%s", e.what());
+  }
+  c->reschedule_save_game_data_event();
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // Administration commands
 
@@ -1695,6 +1718,7 @@ static const unordered_map<string, ChatCommandDefinition> chat_commands({
     {"$qsync", {server_command_qsync, nullptr}},
     {"$quest", {server_command_quest, nullptr}},
     {"$rand", {server_command_rand, proxy_command_rand}},
+    {"$save", {server_command_save, nullptr}},
     {"$saverec", {server_command_saverec, nullptr}},
     {"$sc", {server_command_send_client, proxy_command_send_client}},
     {"$secid", {server_command_secid, proxy_command_secid}},

src/Client.cc

@@ -179,10 +179,7 @@ Client::Client(
   this->last_switch_enabled_command.header.subcommand = 0;
   memset(&this->next_connection_addr, 0, sizeof(this->next_connection_addr));
 
-  if (this->version() == GameVersion::BB) {
-    struct timeval tv = usecs_to_timeval(60000000); // 1 minute
-    event_add(this->save_game_data_event.get(), &tv);
-  }
+  this->reschedule_save_game_data_event();
   this->reschedule_ping_and_timeout_events();
 
   this->log.info("Created");
@@ -199,6 +196,13 @@ Client::~Client() {
   this->log.info("Deleted");
 }
 
+void Client::reschedule_save_game_data_event() {
+  if (this->version() == GameVersion::BB) {
+    struct timeval tv = usecs_to_timeval(60000000); // 1 minute
+    event_add(this->save_game_data_event.get(), &tv);
+  }
+}
+
 void Client::reschedule_ping_and_timeout_events() {
   struct timeval ping_tv = usecs_to_timeval(30000000); // 30 seconds
   event_add(this->send_ping_event.get(), &ping_tv);

src/Client.hh

@@ -218,6 +218,7 @@ struct Client : public std::enable_shared_from_this<Client> {
       ServerBehavior server_behavior);
   ~Client();
 
+  void reschedule_save_game_data_event();
   void reschedule_ping_and_timeout_events();
 
   inline GameVersion version() const {