[Feature Request] Add support for server-side localization (ru_ru and others) for advancements messages

[UrbanSide]

Hello! Thank you for your work on DCIntegration.

I found an important limitation in the current version (Fabric 1.20.1):

❗ Problem

DCIntegration always sends advancement and system messages in English ("en_us"), even if the players on the server use other languages (for example, Russian "ru_ru").
This happens because Minecraft Dedicated Server supports only en_us and does not load other language files.

As a result:

• In-game (client) advancements are shown in the player's language (ru_ru)
• In Discord, all advancement messages from DCIntegration appear only in English

This is confusing for Russian-speaking (or any non-English) communities.

✔️ Suggested Feature

Please add support for:

1. Loading custom language files from: config/dcintegration/lang/<locale>.json or from mod resources.
2. Selecting preferred language in config: language = "ru_ru"
3. Fallback to en_us if translation key is missing.

✔️ Why this is important

• Many servers use DCIntegration in non-English communities
• Advancements and system messages in Discord look inconsistent
• Adding this requires minimal changes: loading a JSON (just like vanilla lang format) and replacing server strings before sending them to Discord

✔️ Optional

If possible, also allow overriding names/descriptions of advancements using:

advancements.[namespace].[path].name
advancements.[namespace].[path].description

ℹ️ Additional Notes

I checked the current source code — DCIntegration does not load any external lang files and always uses server-provided English strings.
Adding localization support would help many servers.

Thank you for considering this request!