[Add] Japanese Language Support

[keshav-k3]

Add Japanese Language Support

Summary

Add Japanese (🇯🇵) translations to the existing multi-language translation system.

Current State

The app currently supports 6 languages:

• 🇺🇸 English
• 🇪🇸 Spanish
• 🇫🇷 French
• 🇮🇳 Hindi
• 🇩🇪 German
• 🇧🇷 Portuguese

Requested Change

Add Japanese translations for all 15 UI text elements:

• Form labels (email, password, name fields)
• Account and room naming prompts
• Welcome and invitation messages
• Bot configuration text
• Browser compatibility warnings

Expected Result

Users will see Japanese as a 7th language option in all translation dropdowns throughout the application.

Implementation

• Add Japanese translations to TRANSLATIONS hash in app/helpers/translations_helper.rb
• Use 🇯🇵 flag emoji to match existing pattern
• No other files require changes (UI automatically updates)

[keshav-k3]

If a decision is made to implement this 👇
#25

[monorkin]

I just merged your PR, thank you for the contribution