feat: added language translation workflow

.gitignore

@@ -1 +1,12 @@
-.DS_Store
+.DS_Store
+
+# Translation pipeline
+.translation-cache.json
+.env
+
+# TypeScript
+dist/
+*.tsbuildinfo
+
+# Node.js
+node_modules

TRANSLATION.md

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+# Multi-Language Translation Pipeline
+
+This document explains how to use the automated translation pipeline for Dodo Payments documentation.
+
+## Quick Start
+
+1. **Install dependencies:**
+   ```bash
+   npm install
+   ```
+
+2. **Set up your OpenAI API key:**
+   ```bash
+   cp .env.example .env
+   # Edit .env and add: OPENAI_API_KEY=your_key_here
+   ```
+
+3. **Run translation:**
+   ```bash
+   npm run translate
+   ```
+
+4. **Update navigation:**
+   ```bash
+   npm run update-nav
+   ```
+
+## Supported Languages
+
+- 🇬🇧 English (en) - Source language
+- 🇨🇳 Chinese Simplified (zh)
+- 🇫🇷 French (fr)
+- 🇩🇪 German (de)
+- 🇮🇩 Indonesian (id)
+- 🇯🇵 Japanese (ja)
+- 🇰🇷 Korean (ko)
+- 🇧🇷 Portuguese Brazil (pt-BR)
+- 🇪🇸 Spanish (es)
+
+## How It Works
+
+### 1. File Discovery
+The pipeline scans all `.mdx` files in your repository (excluding language directories and build files).
+
+### 2. Content Parsing
+Each MDX file is parsed to extract:
+- **Frontmatter** (title, description, etc.) - Translated
+- **Body text** - Translated
+- **Code blocks** (```language) - Preserved as-is
+- **Inline code** (`code`) - Preserved as-is
+- **Mintlify components** - Text content translated, structure preserved
+- **Links and images** - URLs preserved, alt text translated
+
+### 3. Translation
+Uses OpenAI GPT-4o with specialized prompts that:
+- Preserve technical terms (Dodo Payments, API, SDK, etc.)
+- Maintain code syntax
+- Keep URLs and file paths unchanged
+- Translate user-facing content appropriately
+
+### 4. File Generation
+Creates translated files in language-specific directories:
+```
+docs/
+├── introduction.mdx          # English (source)
+├── es/
+│   └── introduction.mdx      # Spanish
+├── fr/
+│   └── introduction.mdx      # French
+└── ...
+```
+
+### 5. Navigation Update
+Updates `docs.json` to use Mintlify's multi-language navigation structure.
+
+## Commands
+
+### Translate (Incremental)
+Only translates files that are new or have been modified:
+```bash
+npm run translate
+```
+
+### Translate (Full)
+Re-translates all files regardless of cache:
+```bash
+npm run translate:full
+```
+
+### Translate Specific Language
+```bash
+npm run translate:lang -- --lang=es
+```
+
+### Update Navigation
+After translation, update the navigation structure:
+```bash
+npm run update-nav
+```
+
+## Translation Cache
+
+The pipeline maintains `.translation-cache.json` to track:
+- Which files have been translated
+- When source files were last modified
+- File hashes for change detection
+
+To clear the cache:
+```bash
+rm .translation-cache.json
+```
+
+## Cost Estimation
+
+- **Model**: GPT-4o
+- **Average cost per page**: ~$0.01-0.03 per language
+- **Total pages**: ~200+ MDX files
+- **Estimated cost for full translation**: ~$15-50 (one-time)
+
+Subsequent runs (incremental) will only translate changed files, significantly reducing costs.
+
+## Troubleshooting
+
+### API Rate Limits
+If you hit rate limits, wait a few minutes and re-run. The cache prevents re-translating completed files.
+
+### Translation Quality Issues
+- Technical terms should be preserved automatically
+- Review translated files and manually adjust if needed
+- Source English files remain unchanged
+
+### Missing Translations
+If a file wasn't translated:
+1. Check the error messages in the console
+2. Delete the cache entry for that file
+3. Re-run the translation
+
+## Workflow
+
+### Initial Setup
+1. Run `npm run translate` to translate all files
+2. Run `npm run update-nav` to update navigation
+3. Review translated files
+4. Commit changes
+
+### Ongoing Updates
+1. Edit English source files
+2. Run `npm run translate` (only changed files will be translated)
+3. Review changes
+4. Commit
+
+## Notes
+
+- English files stay in the root directory
+- Translated files are in language subdirectories
+- Mintlify automatically handles language switching
+- Code examples are preserved in all languages
+- Technical terms and brand names are preserved
+
+## File Structure
+
+```
+dodo-docs/
+├── scripts/
+│   ├── translate.js              # Main translation script
+│   ├── update-navigation.js      # Navigation updater
+│   └── utils/
+│       ├── mdx-parser.js         # MDX content parser
+│       ├── translator.js         # OpenAI translation service
+│       └── cache.js              # Translation cache manager
+├── .translation-cache.json       # Translation cache (gitignored)
+├── .env                          # API keys (gitignored)
+├── package.json
+└── docs.json                     # Updated with multi-language nav
+```
+