feat: add Korean localization

[sampple-korea]

Summary

This PR adds Korean localization support for Operit.

• Added values-ko/strings.xml with Korean translations for user-facing strings.
• Registered Korean in the in-app language selector.
• Added Korean to the string translation helper scripts.
• Connected locales_config.xml through the Android manifest and listed the currently supported app locales.

Translation notes

• Preserved product, provider, and technical terms such as Operit, Memory, Claude, Anthropic, OpenAI, DeepSeek, Ollama, MCP, ToolPkg, API, JSON, Python, Java, and Android.
• Preserved string names, formatting placeholders, escaped characters, and markup.
• Adjusted Korean wording for natural UI usage instead of direct word-for-word substitution.

Validation

• python tools/string/check_strings.py --simple
  • Korean: complete
  • Korean duplicates: 0
• Verified Korean string key parity with the default strings.
• Verified numbered format placeholders are preserved.