feat: add inline note translation

[sato820]

Summary

• add an inline Translate control below note content
• call a configurable LibreTranslate-compatible endpoint with optional API key and target language
• preserve Nostr refs, URLs, lightning/bitcoin IDs, hashtags, and mentions while translating
• cache translations locally by endpoint, target language, and note text hash
• add a Translation settings screen to enable/disable the feature and edit endpoint/API key/language

Verification

• git diff --check
• attempted ./gradlew.bat :app:compileAospDebugKotlin; Gradle starts, but this local machine has no Android SDK configured, so the task stops at SDK location not found before Kotlin compilation.