refactor(Core/DB): Migrate strings from acore_string to module_string

[Nyeriah]

Summary

• Replaces the three acore_string entries (IDs 11120–11122) with module_string entries (IDs 0–2)
• Adds module_string_locale translations for 8 locales: koKR, frFR, deDE, zhCN, zhTW, esES, esMX, ruRU (generated with Copilot)
• Updates PSendSysMessage(LANG_CMD_WEEKEND_XP_*) calls to PSendModuleSysMessage("mod-weekend-xp", id, ...) in the C++ source
• Keeps the cleanup DELETE for old acore_string rows so upgrading servers remove the legacy entries

Test plan

• Apply the SQL and verify rows appear in module_string and module_string_locale
• Confirm old acore_string entries 11120–11122 are removed on upgrade
• Test .weekendxp rate <value> — success and out-of-range error messages display correctly
• Test .weekendxp config — config dump displays correctly
• Verify messages appear in a non-English locale if available

Note

AI tool (Claude Code) was used to assist with this change.

🤖 Generated with Claude Code