Make no-graves command messages configurable in grave.yml

[v4r1n]

Summary

This PR moves the hardcoded "no graves" command responses into the configurable message system under settings.default.default.message in grave.yml, so server owners can translate and restyle them like every other message the plugin sends.

Right now GravesCommand writes these strings inline with ChatColor, which bypasses message.prefix, ignores per-permission overrides, and leaves no way to localize them.

Motivation

Server owners already translate the message: section (for example empty: "You don't have any graves."). The command responses below stay hardcoded in English, so a translated server still shows English text in a different prefix style. This change makes them behave consistently with the rest of the message system.

Changes

New message keys (grave.yml → settings.default.default.message)

no-graves: "You have no graves."
no-graves-other: "&c%name%&r has no graves."

%name% resolves to the target player's name via the existing EntityManager.sendMessage(String, Entity, String name, Location, List<String>) overload.

GravesCommand.java

Self — "You have no graves." (virtual + teleport paths):

plugin.getEntityManager().sendMessage("message.no-graves", player);

Other player — "<name> has no graves." (GUI + virtual + teleport paths):

plugin.getEntityManager().sendMessage("message.no-graves-other", player, args[1],
        player.getLocation(), plugin.getConfigManager().getPermissionList(player));

ConfigManager.java

Bump CURRENT_CONFIG_VERSION so ConfigUpdater merges the new keys into existing server configs on upgrade. ConfigUpdater preserves admin edits and only adds missing keys.

Behavior notes

• Each message now uses the configured message.prefix instead of the inline ☠ » format, matching every other plugin message.
• Setting a key to an empty string disables that message (the existing early-return convention in EntityManager.sendMessage).

Out of scope

This PR intentionally leaves the admin purge responses hardcoded — "No graves found for offline player ..." and "No graves found for UUID ...". Those commands respond to a CommandSender that can be the console, whereas EntityManager.sendMessage only delivers to a Player. Routing them through the message system would silently drop console output and break consistency with the surrounding admin feedback, so they deserve a separate change if desired.

Test plan

• /graves teleport and /graves virtual with no graves → shows no-graves
• /graves teleport <player> / /graves virtual <player> / GUI-other for a player with no graves → shows no-graves-other with correct name
• Set no-graves to "" → no message sends
• Upgrade from a prior config → new keys appear, existing custom messages remain untouched