feat: implement Spanish localization and UI Client translation support

[ArxelDev]

Summary

What changed: Added complete Spanish (es) localization support to the client interface, including translation files, localization service integration, and UI text updates using Tr().

Why: To make Polytoria accessible to Spanish-speaking users, and to allow other language communities to create a translation of the client for their language.

Extra:
I've attached links to Godot's official documentation, which was used for this new feature.
https://docs.godotengine.org/en/stable/tutorials/i18n/internationalizing_games.html
https://docs.godotengine.org/en/stable/tutorials/i18n/localization_using_gettext.html
https://docs.godotengine.org/en/stable/tutorials/i18n/internationalizing_games.html#converting-keys-to-text

Related issue or discussion

Fixes #
Related to #

Type of change

• Bug fix
• New feature
• Refactor
• Tests
• Build/export/tooling
• Other

Area affected

• Client
• Creator
• Server
• Networking / replication
• Scripting API
• Scripting runtimes
• Datamodel
• UI / UX
• Build / export
• Other

Checklist

• I have read the contributing guidelines
• Added in-code documentation (where needed)
• Ran dotnet restore
• Ran dotnet format
• Ran dotnet build
• Ran dotnet test --project Polytoria.Tests/Polytoria.Tests.csproj
• Tested the changes in a local environment
• Ensured all commits are signed off

Screenshots / video

Polytoria.-.Client.2.2026.mp4

AI/LLM use

Used solely for technical advice, the AI never interacted with the code.

[matheussouzadejesus10]

this Is very good :]

[JustBorgar]

Found a couple typos, inconsistencies, and things i'd personally translate differently (there's also a lot of things you translated in 1st person that I think should be in 3rd person, but I wasn't confident enough that was the case to list those).

Besides that, looks pretty good.

[ArxelDev]

Found a couple typos, inconsistencies, and things i'd personally translate differently (there's also a lot of things you translated in 1st person that I think should be in 3rd person, but I wasn't confident enough that was the case to list those).

Besides that, looks pretty good.

@JustBorgar

There are some translations I made on purpose to save space, and others to make them sound more natural. That said, your translations are valid too, which is why I’ll be reviewing your changes.

I’m truly grateful for pointing out the errors—they were details I overlooked, which I need to polish up.

[JustBorgar]

also just a heads up, once you are done with the corrections you'll probably have to do a rebase so the commit is properly signed off, otherwise it won't get merged (unsure if the last commit being signed is good enough or not, maybe ask in the server)

[ArxelDev]

also just a heads up, once you are done with the corrections you'll probably have to do a rebase so the commit is properly signed off, otherwise it won't get merged (unsure if the last commit being signed is good enough or not, maybe ask in the server)

@JustBorgar

Everything you mentioned is ready; all that's left is to merge it.

I'm waiting for your approval, and if anything else is needed or if there are any other similar issues, please don't hesitate to let me know. 🙂

[JustBorgar]

I'm waiting for your approval, and if anything else is needed or if there are any other similar issues, please don't hesitate to let me know. 🙂

Ye looks good, not a maintainer tho, you have to wait for willem to review it