migrate hints system to a localized markdown-based architecture and refactor related UI components

app/src/main/assets/hints/translation_hint.md

@@ -0,0 +1,67 @@
+# Translation Features
+
+Discover the powerful translation capabilities of this app.
+
+## Alternative Translations
+
+Sometimes a word has multiple meanings:
+- Tap the **Show alternatives** option
+- See all possible translations
+- Choose the most appropriate context
+
+## Custom Prompts
+
+Customize how translations are generated:
+
+### Create Custom Prompt
+
+1. Go to Settings → Translation
+2. Tap **Add Custom Prompt**
+3. Write your prompt template
+4. Save and use in translations
+
+### Example Prompts
+
+```
+Translate {word} as used in {context}
+
+Provide formal translation of: {word}
+
+Casual translation for: {word}
+```
+
+## Multiple Translation Services
+
+Use different translation backends:
+
+| Service | Best For | Languages |
+|---------|----------|-----------|
+| AI Models | Context-aware | Many |
+| Dictionary | Quick lookup | Limited |
+| Online API | Accuracy | All |
+
+## Translation History
+
+Track all your translations:
+- Automatically saved
+- Search by word or date
+- Export for review
+
+## Text-to-Speech (TTS)
+
+Hear words pronounced:
+- Tap the **speaker icon**
+- Choose voice for each language
+- Adjust speed as needed
+
+## Quick Actions
+
+Fast access to common tasks:
+
+- **Copy** - Copy translation to clipboard
+- **Add** - Add directly to vocabulary
+- **Share** - Send to other apps
+
+---
+
+*Pro Tip: Use custom prompts for domain-specific vocabulary!*